Prof. Ruixiang Bai, Dalian University of Technology, China
Professor, Department of engineering mechanics, Dalian University of technology, doctoral supervisor, a permanent member of State Key Laboratory of Structural Analysis for Industrial Equipment, Director of China Society for Composite Materials, "Hundred, Thousand, and Ten Thousand Talents Project" in Liaoning province. The main research directions include micromechanical analysis and design of advanced materials, damage and bearing capacity of damaged engineering structures, dynamics and fault diagnosis of composite structures, analysis and numerical simulation of composite engineering structures, repair and strengthening mechanism of damaged engineering structures. He has presided over and participated in a number of major national projects and NSFC projects. In recent years, he has been responsible for more than 20 projects of failure behavior tests and numerical simulations of composite structures in aerospace engineering such as national large aircraft and lunar exploration. Nearly 200 academic papers have been published, and more than 50 papers have been indexed by SCI.
Title: Study on characterization of interface parameters and crack propagation of composite laminates considering fiber laying direction
Abstract: Continuous carbon fiber reinforced polymer composites (CFRP) are commonly used in aircraft structure design. The interface stress is easy to cause interlaminar delamination, resulting in crack propagation and early failure of the structure. In this work, the influence of fiber laying direction and the fiber bridging behavior at the crack tip during delamination propagation are fully considered. The meso interface debonding of carbon fiber/ polymer system, the interface fracture and fatigue crack propagation behavior of composite two-phase materials are systematically studied. With the test methods and fracture mechanics methods, the interface failure behavior of fiber/ polymer interface and laminate are deeply evaluated.
Firstly, this work develops the micro-droplet virtual test method, analyzes the influence of component phase material parameters, geometric parameters and curing temperature on the interface strength, and finds the main controlling factors of debonding failure mode. In the numerical model, the flexibility of the free section of the fiber in the test process and the residual stress produced by high-temperature curing are considered. The stress transfer mechanism and failure mechanism of the interface between the reinforced fiber and the resin matrix in the process of droplet debonding are analyzed from three typical stages.
Secondly, considering the influence of local adjacent ply fiber direction, the characterization method of fiber laying direction related delamination fracture toughness is developed, and the fiber bridging behavior produced in delamination propagation and its contribution to fracture toughness are discussed. The mode I and mode II delamination specimens with six different ply interfaces were designed. The modified beam theory data reduction scheme is used to characterize the mode I fracture toughness of different ply interfaces. Based on the "Jump" phenomenon in the fracture process, the scattered points of R curve are filtered. The delamination failure mechanism of different local ply interfaces is analyzed. The mode II fracture toughness of different ply interfaces was characterized and compared by compliance method by NPC and PC experiments.
Thirdly, based on the cohesive zone model (CZM) of finite element method, the mode I fracture behavior of different ply interfaces is predicted by trilinear traction-separation criterion, and the effective interlaminar interface parameters are characterized, and the traction-separation relationship of mode II delamination interface is characterized by bilinear CZM, and the mode II delamination fracture process of different ply interfaces is reproduced in ABAQUS. The axial compression finite element model of rectangular laminates with circular embedded delamination is established. The deformation of the specimen surface is measured and the displacement field is reconstructed by using 3D-DIC, and the effectiveness of the proposed interface model is proved by comparing with the finite element results.
Prof. Gang Shao, Zhengzhou University, China
Prof. /Dr. Gang Shao received his Ph.D. degree in Department of Materials Science and Engineering from University of Central Florida, Orlando, USA. Currently, he is a professor in School of Materials Science and Engineering, Zhengzhou University (China). His research interests include polymer-derived ceramics (PDCs), harsh environment sensing materials and devices and field assist ceramic fabrication technique. Dr. Shao has published more than 70 peer-reviewed papers including 7 ESI highly cited papers. Dr. Shao has given more than 10 keynote and/or invited talks.
Prof. Fanian Shi, Shenyang University of Technology, China
Fanian Shi, Ph. D., Professor of Shenyang University of Technology, supervisor, member of Energy and Environment Committee of China Energy Society, executive director of the first Board of Directors of the National for the Development of New Materials and Technology. From 1991 to 1996, studied for his master's degree in the National Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences; from 1996 to 2001, worked in the National Key Laboratory of Coordination Chemistry, Nanjing University for postdoctoral research and teaching (associate professor) at Nanjing Normal University; and from 2001 to 2014, worked as a postdoctoral and research fellow in the Department of Chemistry, Aveiro University, Portugal. At present, the main research areas include: design and structure optimization of metal complex materials, composite materials, lithium ion battery materials, photocatalysts, absorbing materials and so on. More than 130 academic papers were published, of which more than 120 were SCI indexed, including Journal of the American Chemical Society、Chemcomm、Acs Sustainable Chemistry & Engineering etc. Presided over the National Natural Science Foundation of China project, Liaoning Province Department of Education key project. As President of the Conference, the International Conference on New Materials was successfully held at Shenyang University of Technology in September 2019(NMS-XV IUPAC).
Title: Study on rare-earth stabilized metal oxides as anode materials
Abstract: Our team studied the electrochemical properties of new anode materials, especially the preparation of manganese-cobalt-nickel-based polymetal coordination polymers (CPs), explored the structures and lithium storage properties of lithium ionic batteries (Libs), the combination of CPs, metal oxides, and the influence of rare earth elements on lithium storage properties of the oxide composites. The following three conclusions are summarized: 1. Under the same conditions, different crystal structures have a great impact on electrochemical performance, relatively speaking, the higher capacity of complexes are with more stable structure; 2. Comparing with polymetallic coordination polymers of the same structure, the electrochemical properties of manganese-cobalt and nickel are different; 3. Cerium plays a stable role on the electrochemical properties of metal complexes, mainly inhibiting the decomposition of the complex structure and providing lithium ion transport channels to improve lithium storage performance.