Papers by Keyword: Laminated Composite

Abstract: The problem of application of the material selection optimization approach for structural-acoustic optimization is investigated. By introducing the stacking sequence hypothesis of metal material, the mechanical parameters of the material and plies number are defined as design variables; the mathematical model of material selection optimization for reducing acoustic power is established. Take a hexahedral box structure for example; the material selection optimization is carried out. The example shows that the vibration and acoustic radiation of composite laminated can be reduced by using material selection optimization method.

Abstract: Based on Mindlin first order shear effect plate theory, the structural-acoustic optimization of laminated composite structures under external loading was investigated. For improving the optimization efficiency, the response surfaces method (RSM) is introduced, and the uniform Latin square method was used to select the most appropriate sample points. In the end, taking the laminated composite plate acoustic radiation as an example, the mathematical model of structural structural-acoustic optimization is established. The results show that the acoustic radiation of laminated composite structures can be reduced by optimizing the stacking sequence parameters such as layers thickness and layers angle. The results prove the validity of the calculating ways.

Abstract: In this study, a buckling analysis is performed on rectangular composite plates with single and double circular notch using the finite element method. Laminated plates of carbon/bismaleimde (IM7/5250-4) are ordered symmetrically as follows [(θ/-θ)2]S. The buckling strength of symmetric laminated plates subjected to uniaxial compression is highlighted as a function of the fibers orientations. The results show that whatever the notch radius, the buckling load is almost stable. Increasing the degree of anisotropy significantly improves critical buckling load.

Abstract: A new type of laminated composite with B4C particle reinforced Al matrix composites as its inner layer and metal Al as outer layer was fabricated by powder metallurgy process. The effects of sintering time on the density and the mechanical properties of Al/B4C laminated composites were investigated. In the inner layer, Vicker’s hardness was enhanced with the addition of B4C. With the extension of sintering time from 2h to 4h at 300°C, aggregation of B4C particles reduced, while the density and Vicker’s hardness improved.

Abstract: This study deals with effects depending on skew angles in skewed-laminated composite materials in macroscopic point of view. Based on higher-order approximation of displacements, subparametric layer-wise finite elements are used to analyze skewed-laminated composite systems. The elements have higher-order shape functions derived from the Lobatto shape functions. The modes of the elements are classified into three groups such as vertex, side, and internal modes. The vertex modes have physical meaning, while side and internal modes with respect to the increase of order of the Lobatto shape functions do not have physical meaning but improve accuracy of analysis. Therefore, fixing mesh arrangement of present analysis, the quality of the analysis can be enhanced without re-meshing work. The approach based on p-version of finite element method is implemented with three-dimensional elasticity theory, while shape functions are developed by combination of one- and two-dimensional shape functions, not using three-dimensional shape functions. Using the accurate and practical proposed technique, macroscopic behavior of skewed-laminated composite materials is investigated.

Abstract: A kind of laminated composite named Al₂O₃/Nylon/Al with high work of fracture was prepared by a simple process using epoxy resin adhesives as binder in a leaky mold at a pressure of 5 MPa. Light microscopy and scanning electron microscopy were employed to observe the microstructures and crack propagation of the laminated composites. The flexural strength and fracture toughness were measured through three-point bending test, and the work of fracture of the laminated composite was calculated from load-displacement curves of three-point bending test. The experimental results show the composite have low Young's modulus and flexural strength, however, the work of fracture of the laminated composite appears to be high of 2850 J/m², and the fracture toughness reaches about 11 MPa•m^1/2. Analysis of microstructure and crack propagation reveals that the failure of the laminated composite exhibit distinctive characteristic.

Abstract: In this study, the elastic buckling behavior of clamped laminated composite cylindrical shells under external pressure was studied. The Finite Element Method (FEM) was used to predict the critical elastic buckling pressure behavior when composite cylindrical shells were subjected to external pressure. The edges of the cylindrical shell ends were completely constrained to simulate clamped end conditions. The influences of parameters such as wall thickness, fiber angle, number of layers and L/R ratio of laminated composite cylindrical shells on critical buckling pressure were studied. It has been found that the under external pressure, the thickness and the fiber angle of the layers have the most significant effect on the critical buckling pressure.

Abstract: Sandwich plates have been extensively used in many engineering applications such as automotive and aerospace. In the present paper, an accurate finite element model is presented for bending analysis of soft-core rectangular sandwich plates. The sandwich plate is composed of three layers: top and bottom skins and core layer. The core is assumed as a soft orthotropic material and skins are assumed generally unequal laminated composites. Finite element model of the problem has been constructed in the ANSYS 11.0 standard code area. Continuity conditions of transverse shear stresses at the interfaces are satisfied as well as the conditions of zero transverse shear stresses on the upper and lower surfaces of plate. Also transverse flexibility and transverse normal strain and stress of core are considered. The effect of geometrical parameters of the sandwich plate are studied. Comparison of the present results with those of plate theories confirms the accuracy of the proposed model.

Abstract: This paper aims at developing the numerical of delamination in laminated composite structures. Formation of initial delamination and growth of existing delamination in HAT-Section laminated made of plies of unidirectional carbon fiber reinforced epoxy resin is investigated computationally. Tsai-Hill failure method is employed to predict delamination initiation while delamination propagation is analyzed using linear elastic fracture mechanics (LEFM).The techniques based on LEFM that have been utilized successfully within the framework of the finite element method (FEM) for the simulation of delamination growth, the virtual crack closer technique (VCCT). Finally this paper proposes future work for precise prediction of delamination of unidirectional carbon fiber reinforced epoxy resin HAT-Section specimens.

Abstract: Impact analysis of an advanced laminated composite comprising aerospace 2024-T3 aluminum alloy and resin impregnated E-glass fiber layers with different stacking sequences is presented in the paper. The panel under study is subjected to load-time history equivalent to the low velocity crash using FEM software ANSYS 12. Stress values in the laminate are found to be discontinuous at the interfaces whereas the displacements are continuous across the interfaces. The maximum stress and displacement values in the laminate are comparable with those in monolithic aluminum alloy panel of same thickness.