**About the Editors**

**Sergei Alexandrov** is a research professor at the Institute for Problems of Mechanics of the Russian Academy of Science (Moscow, Russia) and a visiting professor at Beihang University (Beijing, China). He received his Ph.D. in Physics and Mathematics in 1990 and DSc in Physics and Mathematics in 1994. He worked as a professor at Moscow Aviation Technology Technical University (Russia), a visiting scientist at ALCOA Technical Center (USA), GKSS Research Centre (Germany), Seoul National University (South Korea) and National Chung Cheng University (Taiwan), and a visiting professor at National San Yat Sen University (Taiwan) University of Franche-Comte (France). His research areas are plasticity theory, fracture mechanics, and their applications to metal forming and structural mechanics. He is a member of the Russian National Committee on Theoretical and Applied Mechanics.

**Lihui Lang** obtained his Ph.D. degree from Harbin Institute of Technology in 1998. He is working now as a full professor and scientific committee member of Stamping and Forging Technology, Plasticity Engineering. His research interests are mainly focused on automotive, aircraft and aerospace fields, and his team research covers hydroforming including sheet hydroforming and tube hydroforming, fiber metal laminates composite, high temperature/pressure forming of powder and gradient function/structure materials, powder technologies, warm/hot forming/hydroforming of lightweight materials, high-efficiency exchanger, and KBE system. He has published more than 200 papers in journals, most of which are cited by SCI and EI. He has published one technical book, "Innovative Hydroforming and Warm/Hot Hydroforming". His research has been supported by the NICHIDAI Die Manufacturing Company Youth Prize. He was awarded the "Thomas Stephen Prize" by the Mechanical Engineering Society of the UK and has obtained more than 30 patents.

### **Preface to "Analysis and Design of Structures Made of Plastically Anisotropic Materials"**

The present monograph contains seven chapters written by authors from several countries. All of these chapters are devoted anisotropic properties of materials. Considering anisotropic material properties is important because these properties significantly affect the behavior of structures and parameters of deformation processes. The corresponding theoretical and experimental methods should be capable of capturing this influence of material anisotropy. The present monograph summarizes new trends and established approaches in the mechanics of anisotropic materials.

> **Sergei Alexandrov, Lihui Lang** *Editors*

### *Article* **Residual Stress Analysis of an Orthotropic Composite Cylinder under Thermal Loading and Unloading**

### **Somayeh Bagherinejad Zarandi 1, Hsiang-Wei Lai 1, Yun-Che Wang 1,\* and Sergey Aizikovich 2,3**


Received: 31 January 2019; Accepted: 27 February 2019; Published: 4 March 2019

**Abstract:** Elastoplastic analysis of a composite cylinder, consisting of an isotropic elastic inclusion surrounded by orthotropic matrix, is conducted via numerical parametric studies for examining its residual stress under thermal cycles. The matrix is assumed to be elastically and plastically orthotropic, and all of its material properties are temperature-dependent (TD). The Hill's anisotropic plasticity material model is adopted. The interface between the inclusion and matrix is perfectly bonded, and the outer boundary of the cylinder is fully constrained. A quasi-static, uniform temperature field is applied to the cylinder, which is analyzed under the plane-strain assumption. The mechanical responses of the composite cylinder are strongly affected by the material symmetry and temperature-dependent material properties. When the temperature-independent material properties are assumed, larger internal stresses at the loading phase are predicted. Furthermore, considering only yield stress being temperature dependent may be insufficient since other TD material parameters may also affect the stress distributions. In addition, plastic orthotropy inducing preferential yielding along certain directions leads to complex residual stress distributions when material properties are temperature-dependent.

**Keywords:** orthotropic plasticity; residual stress; temperature-dependent material properties; composite cylinder; finite element analysis
