Key Engineering Materials Vols. 334-335

Abstract: A two-dimensional progressive failure analysis is conducted to predict the failure loads and modes of carbon-epoxy composite joints under pin-loading. An eight-node laminated shell element is used for the finite element modeling. Post-failure stiffness is evaluated based on the complete unloading model combined with various failure criteria. The comparison of finite element and experimental results shows that the finite element analysis based on the combined maximum stress and Yamada-Sun criteria most accurately predicts the failure loads of the composite laminated joints.

Abstract: In this study, the absolutely recycled plastic wood (ARCPW) was fabricated with post-consumer high density polyethylene (HDPE) and wood flour from the saw mills. The alkaline, silane and maleic anhydride modified polypropylene (MAPP) were used as modifiers to treat wood fiber and improve the interfacial adhesion of ARCPW. Effects of wood fiber length, weight fraction and surface treatment on the mechanical properties of ARCPW were investigated. The flexural fracture surfaces of ARCPW were examined and the fracture mechanism of ARCPW was also analyzed in this paper. The results indicated that ARCPW with wood fiber simultaneously treated by alkaline, silane and MAPP possesses the best mechanical properties. The higher the content of wood fiber, the better the flexural strength of ARPCW. The interfacial adhesion of prepared ARCPW is ideal and a good compatibility between wood fiber and matrix was obtained.

Abstract: This work deals with fundamental frequency optimization in Multi-Layered laminated composite cylindrical shell which is subjected to strength failure criteria (Tsai-Hill) constraint. Anisotropic cylindrical shell has finite length with simply supported conditions at both ends. Three dimensional elasticity approaches is used to obtain the objective functioin. To perform optimization, genetic algorithms (GAs) have been used. But GAs does not have the capability of constraint handling. In this paper penalty method as an auxiliary method for GAs has been used to take into accounts the constraints. Tsai-Hill criteria is used as failure constraint. Finally the results are presented for a multi-layered composite shell.

Abstract: The term Liquid Composite Moulding (LCM) encompasses a growing list of composite manufacturing processes. The focus of this paper is prediction of tooling forces for Resin Transfer Moulding (RTM). Previous experimental work has demonstrated the influence of reinforcement compaction behaviour, which is strongly non-elastic. A viscoelastic compaction model has been developed which addresses both dry and wet response, and is implemented in RTM simulations of simple flat parts. Non-planar geometries introduce a tangential stress acting on mould surfaces, due to shear of the reinforcement. The tooling force analysis is extended to complex parts using an existing RTM filling simulation, LIMS, which has been developed at the University of Delaware.

Abstract: In this paper, new steel matrix composites have been developed by powder metallurgy/HIP and abrasive wear and aluminum sticking resistance of the materials have been investigated. The microstructure examination showed that Co-coated WC reinforcement was partly dissolved in a high speed steel (HSS) matrix and an interface layer of M6C formed, but both Co-coated WC and NbC reinforcements were stable in a high vanadium tool steel (CPM10V) matrix. The NbC reinforcement was also stable in a HSS matrix at the same HIP parameters. Property test results indicate that Co-coated WC-reinforced composites have higher abrasion resistance than the composites with NbC, but the latter possess the lowest aluminum sticking propensity. Compared with unreinforced alloys, abrasion wear resistance of the composites was increased by a factor of 3 to 10, most for the HSS-matrix composites.

Abstract: In this paper, based on the equations of coupled thermo-elasticity, two-scale asymptotic expressions of the temperature and displacement of composite materials under coupled thermo-elasticity condition are set up with the perturbation method. By the multi-scale finite element method, the temperature and 2-order displacement, strain and stress of composite materials with small periodic configuration under coupled thermo-elasticity condition are calculated. Comparing with the results calculated by finite element method with refined meshes, it’s shown that multi-scale method is an efficient method, and the calculation precision is satisfied.

Abstract: Carbon-carbon composites are widely applied in the area of astronautics and aeronautics. As a kind of advanced composites, its properties are known to depend essentially on the technological regimes of its manufacturing processes. This paper is devoted to the modeling of manufacturing processes of the composites and focuses on establishing the processing-microstructure-property relation to enable design of internal architecture to predict and optimize properties.