Micromechanical FE analysis on thermal residual stress and shrinkage behavior of 2.5D woven Cf/Al composites

Abstract

2.5D woven Cf/Al composites were fabricated by vacuum-assisted pressure infiltration method. Thermal shrinkage behavior and residual stress of the composites were investigated using micromechanical analysis and experimental method. The thermal expansion properties of yarn along longitudinal and transverse direction were evaluated by analytical method. Based on the yarn’s structural characteristic, the micromechanical finite element models of composites were established. The calculated macroscopic thermal strain-temperature curve from micromechanical simulation agrees well with the thermal shrinkage curve from the experiments. The simulation results indicate that the warp and weft yarns are in compressive stress state, and the residual stress on weft yarns are higher than that on the warp yarns. However, the matrix alloy is mainly in tensile stress state, and the maximum tensile stress occurs in the matrix alloy near warp yarn’s surface. The over high residual stress between the warp and weft yarns lead to local interface debonding. It is an important technical approach to reduce the residual stress in order to improve the mechanical properties of composites.

Keywords

• 2.5d woven
• cf/al composites
• residual stress
• micromechanics
• finite element analysis