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Behavior of Metallic and Composite Structures
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Behavior of Metallic and Composite Structures

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (1 May 2019) | Viewed by 72421

Special Issue Editor

Prof. Dr. Tomasz Sadowski

E-Mail Website
Guest Editor
Department of Solid Mechanics, Faculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40 Str., 20-618 Lublin, Poland
Interests: continuum damage mechanics of materials and structures; modelling of ceramic polycrystalline materials; modelling of composites: ceramic, metal and polymer matrix, metal and polymer foams, wood and plywood; fracture mechanics of materials under mechanical loading and thermal shock; plates with damage and sandwich structures; experimental testing of materials and structures under: static, cyclic, thermal and impact loading
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear colleague,

Various types of metallic and composite structures are used in modern engineering practice. For aerospace, car industry or civil engineering applications the most important are thin walled structures made of different types of: metallic alloys, fibrous composites, laminates and multifunctional materials with a more complicated geometry of reinforcement including nanoparticles or nanofibres. The current applications in modern engineering require analysis of structures of various properties, shapes and sizes (e.g. aircraft wings) including structural hybrid joints, subjected to different types of loadings: quasi-static, dynamic, cyclic, thermal, impact, penetration, etc.

The advanced metallic and composite structures should satisfy multiple structural functions during operation conditions. Structural functions include mechanical properties like: strength, stiffness, damage resistance, fracture toughness, damping etc. Non-structural functions include: electrical and thermal conductivities, sensing, actuation, energy harvesting, self-healing capability, electromagnetic shielding, etc. 

The aim of this SI is to understand the basic principles of damage growth and fracture processes in advanced metallic and composite structures including also structural joints. Nowadays, it is widely recognized that important macroscopic properties, like the macroscopic stiffness and strength, are governed by processes that occur at one to several scales below the level of observation. A thorough understanding of how these processes influence the reduction of stiffness and strength forms the key to the analysis of existing and the design of improved innovative structural elements.

The study of how these various length scales: nano, micro, meso can be bridged or taken into account simultaneously in multiscale models is particularly attractive for composite materials and structural elements, since they have a well-defined structure at the above specified levels.

Prof. Tomasz Sadowski
Guest Editor

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Keywords

  • Metallic and composite structures
  • Multifunctional materials and structures
  • Classical structures: beams, plates, shells
  • Thin walled structures
  • Damage and fracture processes
  • Theoretical analytical and multiscale modeling
  • Experimental investigations
  • Joints of structural elements
  • Quasi-static, dynamic, cyclic, thermal, impact, penetration loadings

Published Papers (23 papers)

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Research

17 pages, 3010 KiB  
Article
The Effect of Layer Thicknesses in Hybrid Titanium–Carbon Laminates on Low-Velocity Impact Response
by Patryk Jakubczak, Jarosław Bieniaś, Magda Droździel, Piotr Podolak and Aleksandra Harmasz
Materials 2020, 13(1), 103; https://doi.org/10.3390/ma13010103 - 24 Dec 2019
Cited by 24 | Viewed by 2526
Abstract
The purpose of the work was the effect of metal volume fraction of fiber metal laminates on damage after dynamic loads based upon the example of innovative hybrid titanium–carbon composite laminates. The subject of the study was metal–fiber hybrid titanium–carbon composite laminates. Four [...] Read more.
The purpose of the work was the effect of metal volume fraction of fiber metal laminates on damage after dynamic loads based upon the example of innovative hybrid titanium–carbon composite laminates. The subject of the study was metal–fiber hybrid titanium–carbon composite laminates. Four types of hybrid titanium–carbon laminates were designed with various metal volume fraction coefficient but constant thickness. Based on the results, it can be stated that changes in the metal volume fraction coefficient in the range of 0.375–0.6 in constant thickness titanium–carbon composite laminates do not significantly affect their resistance to impacts in the energy range of 5–45 J. It was concluded that there were no significant differences in maximum force values, total contact time, and damage range. Some tendency towards a reduction in the energy accumulation capacity was observed with an increase in thickness of the metal part in relation to the total thickness of the laminate, especially in the lower impact energy range. This can result in the lower bending stiffness of laminates with lower metal content and potential elastic strain of the composite part before the initiation of the fiber damage process. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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16 pages, 8212 KiB  
Article
Fracture Analysis and Shear Strength of Aluminum/CFRP and GFRP Adhesive Joint in Fiber Metal Laminates
by Monika Ostapiuk and Jarosław Bieniaś
Materials 2020, 13(1), 7; https://doi.org/10.3390/ma13010007 - 18 Dec 2019
Cited by 14 | Viewed by 5085
Abstract
Fiber metal laminates (FMLs) were initially developed under the motivation of the aerospace industry. Generally, they consist of aluminum and high strength glass fiber in polymeric layers, but the new challenge is to apply them with a carbon fiber. Pretreatment of aluminum is [...] Read more.
Fiber metal laminates (FMLs) were initially developed under the motivation of the aerospace industry. Generally, they consist of aluminum and high strength glass fiber in polymeric layers, but the new challenge is to apply them with a carbon fiber. Pretreatment of aluminum is the main factor responsible for the adhesion between metallic and polymeric layers. The shear strength test a very popular method in the experimental joint of two components. In this article, the main aim was to compare the surface pretreatment and configuration of fibers in FMLs based on aluminum with glass and carbon fibers. The decisive factor of strength in adhesive or cohesive failure is first the type of fibers, and second, the surface preparation. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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20 pages, 3975 KiB  
Article
Three-Dimensional Free Vibration Analysis of Thermally Loaded FGM Sandwich Plates
by Vyacheslav N. Burlayenko, Tomasz Sadowski and Svetlana Dimitrova
Materials 2019, 12(15), 2377; https://doi.org/10.3390/ma12152377 - 25 Jul 2019
Cited by 19 | Viewed by 3360
Abstract
Using the finite element code ABAQUS and the user-defined material utilities UMAT and UMATHT, a solid brick graded finite element is developed for three-dimensional (3D) modeling of free vibrations of thermally loaded functionally gradient material (FGM) sandwich plates. The mechanical and thermal material [...] Read more.
Using the finite element code ABAQUS and the user-defined material utilities UMAT and UMATHT, a solid brick graded finite element is developed for three-dimensional (3D) modeling of free vibrations of thermally loaded functionally gradient material (FGM) sandwich plates. The mechanical and thermal material properties of the FGM sandwich plates are assumed to vary gradually in the thickness direction, according to a power-law fraction distribution. Benchmark problems are firstly considered to assess the performance and accuracy of the proposed 3D graded finite element. Comparisons with the reference solutions revealed high efficiency and good capabilities of the developed element for the 3D simulations of thermomechanical and vibration responses of FGM sandwich plates. Some parametric studies are carried out for the frequency analysis by varying the volume fraction profile and the temperature distribution across the plate thickness. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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12 pages, 7355 KiB  
Article
The Influence of Single Lap Geometry in Adhesive and Hybrid Joints on Their Load Carrying Capacity
by Przemysław Golewski and Tomasz Sadowski
Materials 2019, 12(12), 1884; https://doi.org/10.3390/ma12121884 - 12 Jun 2019
Cited by 16 | Viewed by 2536
Abstract
The manufacturing technology for adhesive joints is not yet fully optimized, as proved by a large number of papers that have been published in recent years. Future studies on innovative techniques for fabricating adhesive joints should investigate the influence of parameters such as: [...] Read more.
The manufacturing technology for adhesive joints is not yet fully optimized, as proved by a large number of papers that have been published in recent years. Future studies on innovative techniques for fabricating adhesive joints should investigate the influence of parameters such as: (1) The shape of adhesive protrusion, (2) lap dimensions, and (3) cohesive layer reduction in the most efforted regions of the joint. With the application of additional mechanical connectors (e.g., rivets, screws, and welds) in adhesive joints, new hybrid connections can be fabricated. The number of publications in this new field is still relatively small. To fill the gap, this paper presents the results of a numerical analysis of different single lap geometries in (1) pure adhesive and (2) hybrid joints. A total of 13 different models with the same surface area of the adhesive layer were considered. In the case of hybrid joints, the adhesive surface before the application of mechanical connectors was assumed to be the same in every tested case. The numerical analysis of pure adhesive and hybrid joints revealed that the differences in strength led to a 30% decrease in the load capacity of these joints. Therefore, when designing pure adhesive and hybrid joints, special attention should be paid to the shape of the lap between the joined elements. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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21 pages, 5543 KiB  
Article
Optimal Design of Shape Memory Alloy Composite under Deflection Constraint
by Yogesh Gandhi, Alessandro Pirondi and Luca Collini
Materials 2019, 12(11), 1733; https://doi.org/10.3390/ma12111733 - 28 May 2019
Cited by 5 | Viewed by 2787
Abstract
Shape-adaptive or morphing capability in both aerospace structures and wind turbine blade design is regarded as significant to increase aerodynamic performance and simplify mechanisms by reducing the number of moving parts. The underlying bistable behavior of asymmetric cross-ply composites makes them a suitable [...] Read more.
Shape-adaptive or morphing capability in both aerospace structures and wind turbine blade design is regarded as significant to increase aerodynamic performance and simplify mechanisms by reducing the number of moving parts. The underlying bistable behavior of asymmetric cross-ply composites makes them a suitable candidate for morphing applications. To date, various theoretical and experiential studies have been carried out to understand and predict the bistable behavior of asymmetric laminates and especially the curvature obtained in their stable configurations. However, when the bi-stable composite plate is integrated with shape memory alloy wires to control the curvature and to snap from a stable configuration to the other (shape memory alloy composite, SMAC), the identification of the design parameters, namely laminate edge length, ply thickness and ply orientation, is not straightforward. The aim of this article is to present the formulation of an optimization problem for the parameters of an asymmetric composite laminate integrated with pre-stressed shape memory alloys (SMA) wires under bi-stability and a minimum deflection requirement. Wires are modeled as an additional ply placed at the mid-plane of the composite host plate. The optimization problem is solved numerically in MATLAB and optimal design variables are then used to model the SMAC in ABAQUS™. Finite element results are compared against numerical results for validation. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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18 pages, 3186 KiB  
Article
Hybrid Artificial Intelligence Approaches for Predicting Buckling Damage of Steel Columns Under Axial Compression
by Lu Minh Le, Hai-Bang Ly, Binh Thai Pham, Vuong Minh Le, Tuan Anh Pham, Duy-Hung Nguyen, Xuan-Tuan Tran and Tien-Thinh Le
Materials 2019, 12(10), 1670; https://doi.org/10.3390/ma12101670 - 22 May 2019
Cited by 73 | Viewed by 5322
Abstract
This study aims to investigate the prediction of critical buckling load of steel columns using two hybrid Artificial Intelligence (AI) models such as Adaptive Neuro-Fuzzy Inference System optimized by Genetic Algorithm (ANFIS-GA) and Adaptive Neuro-Fuzzy Inference System optimized by Particle Swarm Optimization (ANFIS-PSO). [...] Read more.
This study aims to investigate the prediction of critical buckling load of steel columns using two hybrid Artificial Intelligence (AI) models such as Adaptive Neuro-Fuzzy Inference System optimized by Genetic Algorithm (ANFIS-GA) and Adaptive Neuro-Fuzzy Inference System optimized by Particle Swarm Optimization (ANFIS-PSO). For this purpose, a total number of 57 experimental buckling tests of novel high strength steel Y-section columns were collected from the available literature to generate the dataset for training and validating the two proposed AI models. Quality assessment criteria such as coefficient of determination (R2), Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE) were used to validate and evaluate the performance of the prediction models. Results showed that both ANFIS-GA and ANFIS-PSO had a strong ability in predicting the buckling load of steel columns, but ANFIS-PSO (R2 = 0.929, RMSE = 60.522 and MAE = 44.044) was slightly better than ANFIS-GA (R2 = 0.916, RMSE = 65.371 and MAE = 48.588). The two models were also robust even with the presence of input variability, as investigated via Monte Carlo simulations. This study showed that the hybrid AI techniques could help constructing an efficient numerical tool for buckling analysis. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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13 pages, 5051 KiB  
Article
Temperature Effects during Impact Testing of a Two-Phase Metal-Ceramic Composite Material
by Eligiusz Postek and Tomasz Sadowski
Materials 2019, 12(10), 1629; https://doi.org/10.3390/ma12101629 - 17 May 2019
Cited by 5 | Viewed by 2355
Abstract
Metal-ceramic composite (MCC) materials can be used for manufacturing high-responsibility structures such as jet engines or cutting tools. One example of these materials is a two-phase wolfram carbide (WC) and cobalt (Co) composite. This MCC is a combination of hard WC grains with [...] Read more.
Metal-ceramic composite (MCC) materials can be used for manufacturing high-responsibility structures such as jet engines or cutting tools. One example of these materials is a two-phase wolfram carbide (WC) and cobalt (Co) composite. This MCC is a combination of hard WC grains with a Co metallic ductile binder. The resulting microstructure is a combination of two phases with significantly different mechanical behaviors. In this study, we investigate impact conditions, starting with an illustrative example of the Taylor impact bar where—although the process is very rapid—the equivalent plastic strain and temperature are higher in the adiabatic solution than those in the coupled solution. On exposing the WC/Co composite with a metallic binder to impact loading, heat is generated by plastic deformation. If the process is fast enough, the problem can be treated as adiabatic. However, a more common situation is that the process is slower, and the heat is generated in the ductile metallic binders. As a result, the associated grains are heated due to the conduction effect. Consequently, the process should be treated as coupled. When the impact is applied over a short time period, maximum temperatures are significantly lower if the process is analyzed as coupled rather than as adiabatic. The grains are immediately affected by temperature increase in the binders. Therefore, the heat conduction effect should not be omitted. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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12 pages, 1535 KiB  
Article
Mode I Interlaminar Fracture of Glass/Epoxy Unidirectional Laminates. Part I: Experimental Studies
by Sylwester Samborski, Adrian Gliszczynski, Jakub Rzeczkowski and Nina Wiacek
Materials 2019, 12(10), 1607; https://doi.org/10.3390/ma12101607 - 16 May 2019
Cited by 22 | Viewed by 2811
Abstract
The paper presents experimental tests of unidirectional double cantilever beams made of a glass fiber reinforced (GFRP) laminate. The critical value of the strain energy release rate (c-SERR or GIC), i.e., the mode I fracture toughness of the considered material was [...] Read more.
The paper presents experimental tests of unidirectional double cantilever beams made of a glass fiber reinforced (GFRP) laminate. The critical value of the strain energy release rate (c-SERR or GIC), i.e., the mode I fracture toughness of the considered material was determined with three different methods: the compliance calibration method (CC), the modified compliance calibration method (MCC), and the corrected beam theory (CBT). Due to the common difficulties in precise definition of delamination initiation force, the Acoustic Emission (AE) technique was applied as an auxiliary source of data. The failure process was monitored, as well, in order to detect and identify different damage phenomena. This was achieved through a detailed analysis of the raw AE signal subjected to fast Fourier transformation (FFT). The frequency spectra revealed three dominating frequency bands with the basic one described by the average value of 63.1 kHz, revealing intensive delamination processes. This way, not only precise values of the critical SERR, but also the information on damage evolution during propagation of delamination, was obtained. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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18 pages, 4903 KiB  
Article
Mode I Interlaminar Fracture of Glass/Epoxy Unidirectional Laminates. Part II: Numerical Analysis
by A. Gliszczynski, S. Samborski, N. Wiacek and J. Rzeczkowski
Materials 2019, 12(10), 1604; https://doi.org/10.3390/ma12101604 - 16 May 2019
Cited by 19 | Viewed by 3071
Abstract
The paper deals with numerical analysis of double cantilever beam (DCB) predefined to Mode I Interlaminar Fracture Tests of GRFP unidirectional laminates. The numerical analyses were performed in the ANSYS® program based on the finite element. In geometrically nonlinear analysis, two algorithms, [...] Read more.
The paper deals with numerical analysis of double cantilever beam (DCB) predefined to Mode I Interlaminar Fracture Tests of GRFP unidirectional laminates. The numerical analyses were performed in the ANSYS® program based on the finite element. In geometrically nonlinear analysis, two algorithms, responsible for initiation and propagation of delamination front, were applied: Virtual Crack Closure Technique (VCCT) and Cohesive zone method (CZM). Due to the unidirectional arrangement of layers of the laminate, the problem of DCB test was solved with the use of one- and three-dimensional models with the implementation of linear interface element and contact element. The present study highlights the limitations of existing formulae used to reliably reflect the behavior of DCB. The use of three-dimensional models allowed confirming the curved shape of the delamination front observed in experimental studies. The application of the VCCT in the three-dimensional model led to an underestimation of the global response (force–opening displacement curve) recorded during numerical DCB test. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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14 pages, 5450 KiB  
Article
Investigation of the In-Plane Mechanical Anisotropy of Magnesium Alloy AZ31B-O by VPSC–TDT Crystal Plasticity Model
by Bo Zhang, Shuangming Li, Huamiao Wang, Weiqin Tang, Yaodong Jiang and Peidong Wu
Materials 2019, 12(10), 1590; https://doi.org/10.3390/ma12101590 - 15 May 2019
Cited by 7 | Viewed by 2828
Abstract
The in-plane mechanical anisotropy of magnesium alloy sheet, which significantly influences the design of the parts produced by Mg alloy sheets, is of great importance regarding its wide application. Though the stress–strain response and texture evolution have been intensively investigated, and the anisotropy [...] Read more.
The in-plane mechanical anisotropy of magnesium alloy sheet, which significantly influences the design of the parts produced by Mg alloy sheets, is of great importance regarding its wide application. Though the stress–strain response and texture evolution have been intensively investigated, and the anisotropy of Mg alloy can be significantly substantiated by its R-value, which reveals the lateral response of a material other than the primary response. As a consequence, the conjunction of viscoplastic self-consistent model and twinning and detwinning scheme (VPSC–TDT) is employed to investigate the in-plane anisotropy of magnesium alloy AZ31B-O sheet. The loading cases include both tension and compression along different paths with respect to the processing direction of the sheet. It is revealed that the stress–strain relation, texture evolution, R-value, and involved deformation mechanisms are all loading path-dependent. The unique R-values of Mg alloys are interpreted with the aid of modeling behaviors of Mg single crystals. The results agree well with the corresponding experiments. It is found that the hexagonal close-packed (HCP) crystallographic structure, deformation twinning, and initial basal texture are responsible for the characteristic behavior of Mg alloys. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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11 pages, 3186 KiB  
Article
Effects of Adhesive Bond-Slip Behavior on the Capacity of Innovative FRP Retrofits for Fatigue and Fracture Repair of Hydraulic Steel Structures
by Christine M. Lozano and Guillermo A. Riveros
Materials 2019, 12(9), 1495; https://doi.org/10.3390/ma12091495 - 08 May 2019
Cited by 6 | Viewed by 2495
Abstract
Over eighty percent of the navigation steel structures (NSS) in the United States have highly deteriorated design boundary conditions, resulting in overloads that cause fatigue cracking. The NSSs’ highly corrosive environment and deterioration of the protective system accelerate the fatigue cracking and cause [...] Read more.
Over eighty percent of the navigation steel structures (NSS) in the United States have highly deteriorated design boundary conditions, resulting in overloads that cause fatigue cracking. The NSSs’ highly corrosive environment and deterioration of the protective system accelerate the fatigue cracking and cause standard crack repair methods to become ineffective. Numerous studies have assessed and demonstrated the use of carbon fiber reinforced polymers (CFRP) to rehabilitate aging and deteriorated reinforced concrete infrastructure in the aerospace industry. Due to the increase of fatigue and fracture failures of NSS and the shortage of research on CFRP retrofits for submerged steel structures, it is imperative to conduct research on the effects of CFRP repairs on NSS, specifically on the adhesive’s chemical bonding to the steel substrate. This was accomplished by developing a new analytical algorithm for CFRP bond-slip behavior, which is based on Volkersen’s contact shear single lap joint (SLJ) connection. The algorithm was validated by experimental results of fatigue center-cracked large steel plates repaired with CFRP patches. The state of stresses at the crack tip are largely influenced by a combination of the crack tip plasticity radius and overall bond surface area. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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13 pages, 7266 KiB  
Article
The Influence of TBC Aging on Crack Propagation Due to Foreign Object Impact
by Przemysław Golewski and Tomasz Sadowski
Materials 2019, 12(9), 1488; https://doi.org/10.3390/ma12091488 - 08 May 2019
Cited by 13 | Viewed by 2505
Abstract
While a plane is maneuvering before take-off and landing, some solid particles (e.g. sand, dust, soil) may get into the engine with air. A vast majority of them are stopped by the compressor blades, but the smaller ones can get into a hot [...] Read more.
While a plane is maneuvering before take-off and landing, some solid particles (e.g. sand, dust, soil) may get into the engine with air. A vast majority of them are stopped by the compressor blades, but the smaller ones can get into a hot part of the engine and cause erosion. A pneumatic laboratory work station was built in order to investigate the impact of foreign object damage (FOD) particles with a diameter of 4 mm. Cylindrical samples with a diameter of 30 mm were used, each having a thermal barrier coating (TBC) deposited by the air plasma spray (APS) method with the application of yttria-stabilized zirconia (YSZ). Sample aging was performed for four ranges: 48, 89, 185, and 353 h at the temperature of 1000 °C. After aging, samples were subjected to impacts made with different energies. Various damage images were captured depending on the aging time and impact velocity. Numerical studies led to the determination of how the incidence angle of a foreign object and the blade temperature affected the number of elements that became damaged during impact. It was found that impacts perpendicular to the surface were the most dangerous, while heating the blade to the operating temperature resulted in a 27% decrease in the number of elements damaged during impact when compared to the cold blade. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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17 pages, 2835 KiB  
Article
Interactive Buckling of Steel LC-Beams Under Bending
by Zbigniew Kolakowski and Jacek Jankowski
Materials 2019, 12(9), 1440; https://doi.org/10.3390/ma12091440 - 03 May 2019
Cited by 8 | Viewed by 2695
Abstract
The present paper deals with the interactive buckling of thin-walled lipped channel (LC) beams under the bending moment in the web plane when the shear lag phenomenon and distortional deformations are taken into account. A plate model (2D) was adopted for LC beams. [...] Read more.
The present paper deals with the interactive buckling of thin-walled lipped channel (LC) beams under the bending moment in the web plane when the shear lag phenomenon and distortional deformations are taken into account. A plate model (2D) was adopted for LC beams. The structures were assumed to be simply supported at the ends. A modal method of solution to the interactive buckling problem within Koiter’s asymptotic theory, using the semi-analytical method (SAM) and the transition matrix method, was applied. LC-beams, from short through medium-long via long to very long beams, were considered. The paper focuses on the influence of the secondary global buckling mode on the load carrying capacity for the steel LC-beams under bending. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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13 pages, 5253 KiB  
Article
Maximization of FDM-3D-Objects Gonio-Appearance Effects Using PLA and ABS Filaments and Combining Several Printing Parameters: “A Case Study”
by Bàrbara Micó-Vicent, Esther Perales, Khalil Huraibat, Francisco Miguel Martínez-Verdú and Valentín Viqueira
Materials 2019, 12(9), 1423; https://doi.org/10.3390/ma12091423 - 01 May 2019
Cited by 15 | Viewed by 3385
Abstract
In order to consider 3D objects from suitable Fused Deposition Modelling (FDM) printers as prototypes for the automotive sector, this sample must be able to reproduce textural effects (sparkle or graininess) or metallic or gonio-appearance to reinforce the attractive appeal of these materials. [...] Read more.
In order to consider 3D objects from suitable Fused Deposition Modelling (FDM) printers as prototypes for the automotive sector, this sample must be able to reproduce textural effects (sparkle or graininess) or metallic or gonio-appearance to reinforce the attractive appeal of these materials. This study worked with two different commercial filaments: grey metallic PLA (poly(lactic acid)) and ABS (acrylonitrile-butadiene-styrene copolymer) with diffractive pigments. For both materials, a statistical design of experiments (DoE) was carried out to find the printing parameters effect on the final 3D-objects gonio-appearance. The selected printing parameters were printing speed (2 levels), layer height (2 levels) and sample thickness (3 levels). Twelve smooth square objects were printed from each material. The ABS-diffractive filaments achieved the most significant flop and higher sparkle values than metallic PLA. Graininess was high when working with PLA filaments instead of ABS. Layer height was the most significant parameter to maximize PLA objects’ flop or sparkle effects. The best result was found when printing at 0.1 mm. For the ABS samples, the stronger flop and sparkle effects were achieved with the 50 mm/s printing speed, the 0.1 mm layer height and the lowest thickness level. This study shows the methodology to study the printing parameters effects and interactions to maximize the FDM-3D-objects gonio-appearance. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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22 pages, 13653 KiB  
Article
Study of Toughness and Macro/Micro-Crack Development of Fibre-Reinforced Ultra-High Performance Concrete After Exposure to Elevated Temperature
by Piotr Smarzewski
Materials 2019, 12(8), 1210; https://doi.org/10.3390/ma12081210 - 12 Apr 2019
Cited by 38 | Viewed by 3850
Abstract
This study has investigated the changes that might appear in post-peak flexural response. Before the flexural test, prismatic specimens were placed in a furnace chamber and exposed to elevated temperatures of 400, 600, and 800 °C. The flexural toughness test was carried out [...] Read more.
This study has investigated the changes that might appear in post-peak flexural response. Before the flexural test, prismatic specimens were placed in a furnace chamber and exposed to elevated temperatures of 400, 600, and 800 °C. The flexural toughness test was carried out on two types of concrete: Plain ultra-high performance concrete (UHPC) and UHPC with different types of fibres (steel fibre (SF) and polypropylene fibre (PPF)) at 0.5%, 1%, 1.5%, and 2% volume fractions. During the flexural test in the macro-crack development analysis, the non-contact ARAMIS system was used to perform three-dimensional measurements of strain and displacement. The results of scanning electron microscope (SEM) observations of micro-crack development in UHPC without and with SF/PPF were also presented. The experimental results showed that in some cases, the load–deflection curve of fibre-reinforced UHPC displayed a double-peak response. The first peak signified the UHPC properties, while the second peak represented the properties of the fibres. Under flexural load, the toughness decreased as the temperature increased. Significant decrease in the load–deflection response and toughness were observed for the polypropylene fibre-reinforced UHPC when the temperature approached 800 °C. The SEM observation results showed that the thermal damage of fibre-reinforced UHPC depends on the pore pressure effect, the thermal mismatch, the decomposition of hydration products, and the formation of micro-cracks. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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13 pages, 19362 KiB  
Article
Experimental Investigations of Impact Damage Influence on Behavior of Thin-Walled Composite Beam Subjected to Pure Bending
by Tomasz Kubiak, Lukasz Borkowski and Nina Wiacek
Materials 2019, 12(7), 1127; https://doi.org/10.3390/ma12071127 - 06 Apr 2019
Cited by 11 | Viewed by 2957
Abstract
The paper deals with buckling, postbuckling, and failure of pre-damaged channel section beam subjected to pure bending. The channel section beams made of eight-layered GFRP laminate with different symmetrical layups have been considered. The specimens with initially pre-damaged web or flange were investigated [...] Read more.
The paper deals with buckling, postbuckling, and failure of pre-damaged channel section beam subjected to pure bending. The channel section beams made of eight-layered GFRP laminate with different symmetrical layups have been considered. The specimens with initially pre-damaged web or flange were investigated to access the influence of impact damage on work of thin-walled structure in the full range of load till failure. The bending tests of initially pre-damage beams have been performed on a universal tensile machine with especially designed grips. The digital image correlation system allowing to follow the beam deflection have been employed. The experimentally obtained results are presented in graphs presenting load-deflection or load vs. angle of rotation relations and in photos presenting impact damages areas before and after bending test. The results show that the impact pre-damages have no significant influence on the work of channel section beams. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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12 pages, 2455 KiB  
Article
Critical Damage Values of R200 and 100Cr6 Steels Obtained by Hot Tensile Testing
by Zbigniew Pater and Andrzej Gontarz
Materials 2019, 12(7), 1011; https://doi.org/10.3390/ma12071011 - 27 Mar 2019
Cited by 5 | Viewed by 2621
Abstract
The paper proposes a new method for determining critical damage values in hot forming processes. The method first involves performing tensile tests of axisymmetric samples and then simulating these tests numerically. Simulations are performed by the finite element method in a three-dimensional state [...] Read more.
The paper proposes a new method for determining critical damage values in hot forming processes. The method first involves performing tensile tests of axisymmetric samples and then simulating these tests numerically. Simulations are performed by the finite element method in a three-dimensional state of strain, including thermal phenomena occurring in the forming zone. The elaborated method is universal and can be used for different materials. The study is performed for two steel grades, i.e., R200 railway steel and 100Cr6 bearing steel. The results demonstrate that critical damage values strongly depend on the forming temperature. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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12 pages, 18551 KiB  
Article
Numerical Analysis and Its Laboratory Verification in Bending Test of Glue Laminated Timber Pre-Cracked Beam
by Bartosz Kawecki and Jerzy Podgórski
Materials 2019, 12(6), 955; https://doi.org/10.3390/ma12060955 - 22 Mar 2019
Cited by 4 | Viewed by 2843
Abstract
The paper describes an approach to model glue laminated timber (GLT) made of pinewood (softwood), taking into account damage processes in timber and adhesive layers. An example of a pre-cracked beam has been presented. Obtaining necessary material properties has been supported by several [...] Read more.
The paper describes an approach to model glue laminated timber (GLT) made of pinewood (softwood), taking into account damage processes in timber and adhesive layers. An example of a pre-cracked beam has been presented. Obtaining necessary material properties has been supported by several finite elements models (FEM), laboratory tests and a wide literature survey. The authors have taken into consideration an orthotropic material with damage for timber lamellas and isotropic traction separation law for bonding layers. Both plane stress CPS8R and COH2D4 finite elements from the Simulia ABAQUS system or mesh density, used in the numerical analyses, have been carefully chosen and tested. The GLT beam model has been verified on the basis of several values, using two types of testing techniques—MTS 809 machine measurements and digital image correlation (DIC). Additional results revision has been provided by measuring a crack shear displacement (CSD), using the original laboratory test setup by the authors’ idea. Finally, some conclusions and introductory recommendations for modelling a glue laminated timber in a plane stress have been formulated. The paper is a part of a wider research on timber-polymer composites, which is still under development. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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10 pages, 2111 KiB  
Article
The Study of Buckling and Post-Buckling of a Step-Variable FGM Box
by Leszek Czechowski and Zbigniew Kołakowski
Materials 2019, 12(6), 918; https://doi.org/10.3390/ma12060918 - 19 Mar 2019
Cited by 10 | Viewed by 2285
Abstract
This work concerns the analysis of a thin-walled box made of ceramic and step-variable functionally graded material (FGM) subjected to compression. The components of the box taken into account were pure alumina and aluminium-alumina graded material. The problem was solved on the basis [...] Read more.
This work concerns the analysis of a thin-walled box made of ceramic and step-variable functionally graded material (FGM) subjected to compression. The components of the box taken into account were pure alumina and aluminium-alumina graded material. The problem was solved on the basis of a finite element method and Koiter’s asymptotic theory using a semi-analytical method (SAM). It analysed both the buckling state and the post-buckling state of the box. In addition, three conditions were considered: The presence of alumina outside or inside of the box and a mixed case. The obtained results were presented and discussed. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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24 pages, 7720 KiB  
Article
Scale Effects in Orthotropic Composite Assemblies as Micropolar Continua: A Comparison between Weak- and Strong-Form Finite Element Solutions
by Lorenzo Leonetti, Nicholas Fantuzzi, Patrizia Trovalusci and Francesco Tornabene
Materials 2019, 12(5), 758; https://doi.org/10.3390/ma12050758 - 05 Mar 2019
Cited by 34 | Viewed by 2904
Abstract
The aim of the present work was to investigate the mechanical behavior of orthotropic composites, such as masonry assemblies, subjected to localized loads described as micropolar materials. Micropolar models are known to be effective in modeling the actual behavior of microstructured solids in [...] Read more.
The aim of the present work was to investigate the mechanical behavior of orthotropic composites, such as masonry assemblies, subjected to localized loads described as micropolar materials. Micropolar models are known to be effective in modeling the actual behavior of microstructured solids in the presence of localized loads or geometrical discontinuities. This is due to the introduction of an additional degree of freedom (the micro-rotation) in the kinematic model, if compared to the classical continuum and the related strain and stress measures. In particular, it was shown in the literature that brick/block masonry can be satisfactorily modeled as a micropolar continuum, and here it is assumed as a reference orthotropic composite material. The in-plane elastic response of panels made of orthotropic arrangements of bricks of different sizes is analyzed herein. Numerical simulations are provided by comparing weak and strong finite element formulations. The scale effect is investigated, as well as the significant role played by the relative rotation, which is a peculiar strain measure of micropolar continua related to the non-symmetry of strain and work-conjugated stress. In particular, the anisotropic effects accounting for the micropolar moduli, related to the variation of microstructure internal sizes, are highlighted. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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16 pages, 1117 KiB  
Article
Hygrothermal Analysis of Laminated Composite Skew Conoids
by Abhay Chaubey, Ajay Kumar, Stanisław Fic, Danuta Barnat-Hunek and Barbara Sadowska-Buraczewska
Materials 2019, 12(2), 225; https://doi.org/10.3390/ma12020225 - 10 Jan 2019
Cited by 8 | Viewed by 3318
Abstract
The present paper is the first study on the hygrothermal analysis (i.e., effect of temperature and moisture loadings) of laminated composite skew conoids with reasonable depth and thickness. In order to solve the hygrothermal problem of laminated composite skew conoids, the cubic variation [...] Read more.
The present paper is the first study on the hygrothermal analysis (i.e., effect of temperature and moisture loadings) of laminated composite skew conoids with reasonable depth and thickness. In order to solve the hygrothermal problem of laminated composite skew conoids, the cubic variation in displacement field, along with cross curvature effects of the shell, were considered. In the present analysis, the shear correction factor is not needed due to the parabolic variation of transverse shear strain. The zero transverse shear stress conditions at the top and bottom of the shell were imposed in the mathematical model. The novelty of our model is reflected by the simultaneous addition of twist curvature in the strain field, as well as the curvature in the displacement field allowing the reasonably thick and deep laminated composite rhombic conoid. The conoid behavior differs from the usual shells, like cylindrical or spherical ones, due to its inherent twist curvature with the complex geometry and different location of maximum deflection. The finite element (FE) implementation of the present realistic mathematical model was carried out using a nine-noded curved isoparametric element with seven unknowns at each node. The C0 FE implementation of the present mathematical model was done and coded in FORTRAN. The present model results were compared and found in good agreement with other solutions published in the literature. Hygrothermal analysis was performed for skew conoids having a different skew angle, temperature, moisture concentration, curvatures, ply orientation, thickness ratio, and boundary conditions. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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14 pages, 1263 KiB  
Article
Evolution of the Material Microstructures and Mechanical Properties of AA1100 Aluminum Alloy within a Complex Porthole Die during Extrusion
by Ding Tang, Wenli Fang, Xiaohui Fan, Tianxia Zou, Zihan Li, Huamiao Wang, Dayong Li, Yinghong Peng and Peidong Wu
Materials 2019, 12(1), 16; https://doi.org/10.3390/ma12010016 - 20 Dec 2018
Cited by 13 | Viewed by 3943
Abstract
Microchannel tube (MCT) is widely employed in industry due to its excellent efficiency in heat transfer. An MCT is commonly produced through extrusion within a porthole die, where severe plastic deformation is inevitably involved. Moreover, the plastic deformation, which dramatically affects the final [...] Read more.
Microchannel tube (MCT) is widely employed in industry due to its excellent efficiency in heat transfer. An MCT is commonly produced through extrusion within a porthole die, where severe plastic deformation is inevitably involved. Moreover, the plastic deformation, which dramatically affects the final property of the MCT, varies significantly from location to location. In order to understand the development of the microstructure and its effect on the final property of the MCT, the viscoplastic self-consistent (VPSC) model, together with the finite element analysis and the flow line model, is employed in the current study. The flow line model is used to reproduce the local velocity gradient within the complex porthole die, while VPSC model is employed to predict the evolution of the microstructure accordingly. In addition, electron backscatter diffraction (EBSD) measurement and mechanical tests are used to characterize the evolution of the microstructure and the property of the MCT. The simulation results agree well with the corresponding experimental ones. The influence of the material’s flow line on the evolution of the orientation and morphology of the grains, and the property of the produced MCT are discussed in detail. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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19 pages, 2043 KiB  
Article
Flexural and Free Vibration Analysis of CNT-Reinforced Functionally Graded Plate
by Md Irfan Ansari, Ajay Kumar, Stanisław Fic and Danuta Barnat-Hunek
Materials 2018, 11(12), 2387; https://doi.org/10.3390/ma11122387 - 27 Nov 2018
Cited by 23 | Viewed by 2576
Abstract
This paper examines the effect of uniaxially aligned carbon nanotube (CNT) on flexural and free vibration analysis of CNT-reinforced functionally graded plate. The mathematical model includes expansion of Taylor’s series up to the third degree in the thickness co-ordinate. Since there is a [...] Read more.
This paper examines the effect of uniaxially aligned carbon nanotube (CNT) on flexural and free vibration analysis of CNT-reinforced functionally graded plate. The mathematical model includes expansion of Taylor’s series up to the third degree in the thickness co-ordinate. Since there is a parabolic variation in transverse shear strain deformation across the thickness co-ordinate, the shear correction factor is not necessary. A nine-node two-dimensional (2D) C0 isoparametric element containing seven nodal unknowns per node was developed in the finite element code. The final material properties of CNT-reinforced functionally graded plate are estimated using the extended rule of mixture. The effect of CNT distribution, boundary condition, volume fraction and loading pattern are studied by developing a finite element code. An additional finite element code was developed for the study of the influence of concentrated mass on free vibration analysis of CNT-reinforced functionally graded plate. Full article
(This article belongs to the Special Issue Behavior of Metallic and Composite Structures)
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