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13 pages, 3384 KiB

Open AccessArticle

Design of a Highly Adaptable Advance Support for a Deep, Fully Mechanized Roadway and Analysis of Its Support Performance

by Ke Ding, Lianguo Wang, Jiansheng Tian, Bo Ren, Chongyang Jiang and Shuai Wang

Appl. Sci. 2022, 12(24), 12728; https://doi.org/10.3390/app122412728 - 12 Dec 2022

Cited by 3 | Viewed by 1526

Abstract

Considering the harsh environment of deep, fully mechanized working faces and the acutely imbalanced time distribution among excavation, support and anchoring, this paper designed a new type of highly adaptable advance support for fully mechanized roadways that boasts high adaptability, great support strength [...] Read more.

Considering the harsh environment of deep, fully mechanized working faces and the acutely imbalanced time distribution among excavation, support and anchoring, this paper designed a new type of highly adaptable advance support for fully mechanized roadways that boasts high adaptability, great support strength and a large working space. Firstly, the structure composition and working principle of the advance support were introduced. The structures and mechanical characteristics were then emphatically discussed. Subsequently, with the geological conditions of the 8224-machine roadway in the XT Coal Mine taken as an example, the loads of the advance support were obtained and then imported into the Ansys software to obtain the stress distribution and displacement distribution of the whole advance support and its parts through calculation. Based on the distribution, the stress and strain of the advance support were analyzed. The simulation results are as follows: Under various working conditions, the maximum displacement of the advance support was 4.5 mm, which is negligible compared to the overall size of the support; the maximum stress was 72.8 MPa, which is lower than the yield strength of the material (235 MPa). Therefore, the designed support can bear the pressure from the surrounding rock in the mine. Moreover, the roof beam, which is a weak link in the support, deserves more attention in subsequent engineering designs. This method conduces to not only parallel operations of excavation, support and anchoring, but also to rapid excavation and the safe production of roadways, providing fresh ideas for the advance support for fully mechanized roadways. Full article

(This article belongs to the Special Issue Dynamic Phenomena)

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18 pages, 7378 KiB

Open AccessArticle

Energy Consumption Analysis of a Rolling Mechanism Based on a Five-Bow-Shaped-Bar Linkage

by Lianqing Yu, Yong Zhang, Na Feng, Tiandu Zhou, Xiaoshuang Xiong and Yujin Wang

Appl. Sci. 2022, 12(21), 11164; https://doi.org/10.3390/app122111164 - 3 Nov 2022

Cited by 1 | Viewed by 1805

Abstract

To reveal the relationship between the center of mass (CoM) trajectory of a closed five-bow-shaped-bar linkage and its energy consumption, this paper presents a trajectory planning method based on the workspace of the CoM. Using different height points located on the symmetric centerline [...] Read more.

To reveal the relationship between the center of mass (CoM) trajectory of a closed five-bow-shaped-bar linkage and its energy consumption, this paper presents a trajectory planning method based on the workspace of the CoM. Using different height points located on the symmetric centerline of the workspace of the CoM as via points, the CoM trajectory is planned by combining cubic polynomials with Bézier curves based on quadratic Bernstein polynomials. Herein, the system energy consumption is obtained by integrating the product of generalized velocity and generalized force versus time, where the generalized force is calculated by Lagrange’s equation including the Rayleigh dissipation function. Then, two schemes of dynamic rolling are proposed to compare, and the theoretical results show that the system consumes less energy under the sinusoid scheme when the via point height is lower and the via point of higher height is more suitable under the modified trapezoidal curve scheme. Furthermore, this paper combines the locomotion simulation software to design the locomotion of the mechanism’s CoM trajectory under two schemes in detail and verifies the correctness of the theoretical results. Full article

(This article belongs to the Special Issue Dynamic Phenomena)

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11 pages, 4844 KiB

Open AccessArticle

Design and Performance of L-CaPaMan2

by Alexander Titov, Matteo Russo and Marco Ceccarelli

Appl. Sci. 2022, 12(3), 1380; https://doi.org/10.3390/app12031380 - 27 Jan 2022

Cited by 2 | Viewed by 2218

Abstract

The improved solution of L-CaPaMan design is elaborated with solutions for low-cost lightweight features. A new prototype is presented as a result of design improvements by using market components and 3D printing manufacturing. The new prototype as L-CaPaMan (Light CaPaMan) is characterised with [...] Read more.

The improved solution of L-CaPaMan design is elaborated with solutions for low-cost lightweight features. A new prototype is presented as a result of design improvements by using market components and 3D printing manufacturing. The new prototype as L-CaPaMan (Light CaPaMan) is characterised with new components for a new slider solution and light-structure links. The prototype construction is discussed up to a testing layout for design validation and operation characterization. Results of testing are discussed to outline the operation performance of L-CaPaMan by using Arduino controller with basic sensors for motion and action monitoring. Full article

(This article belongs to the Special Issue Dynamic Phenomena)

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36 pages, 6667 KiB

Open AccessArticle

Modeling and Control of an Articulated Multibody Aircraft

by Titilayo Ogunwa, Ermira Abdullah and Javaan Chahl

Appl. Sci. 2022, 12(3), 1162; https://doi.org/10.3390/app12031162 - 23 Jan 2022

Cited by 6 | Viewed by 4500

Abstract

Insects use dynamic articulation and actuation of their abdomen and other appendages to augment aerodynamic flight control. These dynamic phenomena in flight serve many purposes, including maintaining balance, enhancing stability, and extending maneuverability. The behaviors have been observed and measured by biologists but [...] Read more.

Insects use dynamic articulation and actuation of their abdomen and other appendages to augment aerodynamic flight control. These dynamic phenomena in flight serve many purposes, including maintaining balance, enhancing stability, and extending maneuverability. The behaviors have been observed and measured by biologists but have not been well modeled in a flight dynamics framework. Biological appendages are generally comparatively large, actuated in rotation, and serve multiple biological functions. Technological moving masses for flight control have tended to be compact, translational, internally mounted and dedicated to the task. Many flight characteristics of biological flyers far exceed any technological flyers on the same scale. Mathematical tools that support modern control techniques to explore and manage these actuator functions may unlock new opportunities to achieve agility. The compact tensor model of multibody aircraft flight dynamics developed here allows unified dynamic and aerodynamic simulation and control of bioinspired aircraft with wings and any number of idealized appendage masses. The demonstrated aircraft model was a dragonfly-like fixed-wing aircraft. The control effect of the moving abdomen was comparable to the control surfaces, with lateral abdominal motion substituting for an aerodynamic rudder to achieve coordinated turns. Vertical fuselage motion achieved the same effect as an elevator, and included potentially useful transient torque reactions both up and down. The best performance was achieved when both moving masses and control surfaces were employed in the control solution. An aircraft with fuselage actuation combined with conventional control surfaces could be managed with a modern optimal controller designed using the multibody flight dynamics model presented here. Full article

(This article belongs to the Special Issue Dynamic Phenomena)

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23 pages, 5424 KiB

Open AccessArticle

Robust Control for Non-Minimum Phase Systems with Actuator Faults: Application to Aircraft Longitudinal Flight Control

by Aisha Sir Elkhatem, Seref Naci Engin, Amjad Ali Pasha, Mustafa Mutiur Rahman and Subramania Nadaraja Pillai

Appl. Sci. 2021, 11(24), 11705; https://doi.org/10.3390/app112411705 - 9 Dec 2021

Cited by 10 | Viewed by 3547

Abstract

This study is concerned with developing a robust tracking control system that merges the optimal control theory with fractional-order-based control and the heuristic optimization algorithms into a single framework for the non-minimum phase pitch angle dynamics of Boeing 747 aircraft. The main control [...] Read more.

This study is concerned with developing a robust tracking control system that merges the optimal control theory with fractional-order-based control and the heuristic optimization algorithms into a single framework for the non-minimum phase pitch angle dynamics of Boeing 747 aircraft. The main control objective is to deal with the non-minimum phase nature of the aircraft pitching-up action, which is used to increase the altitude. The fractional-order integral controller (FIC) is implemented in the control loop as a pre-compensator to compensate for the non-minimum phase effect. Then, the linear quadratic regulator (LQR) is introduced as an optimal feedback controller to this augmented model ensuring the minimum phase to create an efficient, robust, and stable closed-loop control system. The control problem is formulated in a single objective optimization framework and solved for an optimal feedback gain together with pre-compensator parameters according to an error index and heuristic optimization constraints. The fractional-order integral pre-compensator is replaced by a fractional-order derivative pre-compensator in the proposed structure for comparison in terms of handling the non-minimum phase limitations, the magnitude of gain, phase-margin, and time-response specifications. To further verify the effectiveness of the proposed approach, the LQR-FIC controller is compared with the pole placement controller as a full-state feedback controller that has been successfully applied to control aircraft dynamics in terms of time and frequency domains. The performance, robustness, and internal stability characteristics of the proposed control strategy are validated by simulation studies carried out for flight conditions of fault-free, 50%, and 80% losses of actuator effectiveness. Full article

(This article belongs to the Special Issue Dynamic Phenomena)

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7 pages, 2643 KiB

Open AccessArticle

Micro-Nano Machining TiO₂ Patterns without Residual Layer by Unconventional Imprinting

by Zhoufang Zeng, Gang Shi, Florian Ion Tiberiu Petrescu, Liviu Marian Ungureanu and Ying Li

Appl. Sci. 2021, 11(21), 10097; https://doi.org/10.3390/app112110097 - 28 Oct 2021

Cited by 3 | Viewed by 1639

Abstract

Usually, the residual layer remains after patterning TiO₂ sol. The existence of the TiO₂ residual layer in the non-pattern region affects its application in microelectronic devices. Here, a simple method, based on room-temperature imprinting, to fabricate a residual-free TiO₂ pattern [...] Read more.

Usually, the residual layer remains after patterning TiO₂ sol. The existence of the TiO₂ residual layer in the non-pattern region affects its application in microelectronic devices. Here, a simple method, based on room-temperature imprinting, to fabricate a residual-free TiO₂ pattern is proposed. The thermoplastic polymer with Ti⁴⁺ salt was fast patterned at room temperature by imprinting, based on the different interfacial force. Then, the patterned thermoplastic polymer with Ti⁴⁺ salt was induced into the TiO₂ lines without residual layer under the hydrothermal condition. This method provides a new idea to pattern metal oxide without residual layer, which is potentially applied to the gas sensor, the optical detector and the light emitting diode. Full article

(This article belongs to the Special Issue Dynamic Phenomena)

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23 pages, 6153 KiB

Open AccessFeature PaperArticle

Dynamics of Mechanisms with Superior Couplings

by Liviu Marian Ungureanu and Florian Ion Tiberiu Petrescu

Appl. Sci. 2021, 11(17), 8207; https://doi.org/10.3390/app11178207 - 3 Sep 2021

Cited by 6 | Viewed by 6441

Abstract

The paper briefly presents the dynamic synthesis of mechanisms with superior couplings, force, and speed distribution, efficiency, loss coefficient, dynamic coefficient or motion transmission function, determination of variable angular input speed from the crank or cam based on solving the equation Lagrange, the [...] Read more.

The paper briefly presents the dynamic synthesis of mechanisms with superior couplings, force, and speed distribution, efficiency, loss coefficient, dynamic coefficient or motion transmission function, determination of variable angular input speed from the crank or cam based on solving the equation Lagrange, the determination of the dynamic variation of the follower (adept) based on the integration of Newton’s equation, and the dynamic analysis of several models taken into account. In the end, the original relations for calculating the efficiency of a gear are presented. Full article

(This article belongs to the Special Issue Dynamic Phenomena)

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21 pages, 11022 KiB

Open AccessArticle

Diamond-Shaped Extended Fins for Heat Transfer Enhancement in a Double-Pipe Heat Exchanger: An Innovative Design

by Muhammad Ishaq, Amjad Ali, Muhammad Amjad, Khalid Saifullah Syed and Zafar Iqbal

Appl. Sci. 2021, 11(13), 5954; https://doi.org/10.3390/app11135954 - 26 Jun 2021

Cited by 8 | Viewed by 3595

Abstract

Heat transfer enhancement in heat exchangers results in thermal efficiency and energy saving. In double-pipe heat exchangers (DPHEs), extended or augmented fins in the annulus of the two concentric pipes, i.e., at the outer surface of the inner pipe, are used to extend [...] Read more.

Heat transfer enhancement in heat exchangers results in thermal efficiency and energy saving. In double-pipe heat exchangers (DPHEs), extended or augmented fins in the annulus of the two concentric pipes, i.e., at the outer surface of the inner pipe, are used to extend the surface of contact for enhancing heat transfer. In this article, an innovative diamond-shaped design of extended fins is proposed for DPHEs. This type of fin is considered for the first time in the design of DPHEs. The triangular-shaped and rectangular-shaped fin designs of DPHE, available in the literature, can be recovered as special cases of the proposed design. An h-adaptive finite element method is employed for the solution of the governing equations. The results are computed for various performance measures against the emerging parameters. The results dictate that the optimal configurations of the diamond-shaped fins in the DPHE for an enhanced heat transfer are recommended as follows: If around 4–6, 8–12, or 16–32 fins are to be placed in the DPHE, then the height of the fins should be 20%, 80%, or 100%, respectively, of the annulus width. If frictional loss of heat is also to be considered, then for fin-heights of 20–80% and 100% of the annulus width, the placement of 4 and 8 diamond-shaped fins, respectively, is recommended for an enhanced heat transfer. These recommendations are for the radii ratio (i.e., the ratio of the inner pipe radius to that of the outer pipe) of 0.25. The recommendations are be modified if the radii ratio is altered. Full article

(This article belongs to the Special Issue Dynamic Phenomena)

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