Volumetric changes in non-homogeneous materials

在热固性复合材料的固化过程中，树脂发生交联反应，导致材料密度增加，体积减小。体积缩小的过程，通常被称为化学收缩，会导致高锁紧应力的产生。如附录A所示，热收缩和树脂收缩引起的应力都可能导致聚合物模具的变形和过早开裂。为了设计具有高尺寸公差的复合材料的制造工艺和工具，对固化收缩机制的深入理解对LMAT至关重要。该项目将通过物理测试和数值模拟相结合，提供对材料行为的必要理解，以找到测量固化收缩引起的应变和应力的最佳方法。该项目的成功成果将有助于保持和提高英国在复合材料制造领域的领先地位。

During curing of thermosetting composites the resin undergoes cross-linking reactions that lead to an increase of material density and reduction in volume. The process of volume reduction, usually referred to as chemical shrinkage, can lead to development of high locked-in stresses. Both thermal and resin shrinkage induced stresses can subsequently cause distortion and premature cracking of the polymeric mouldings as shown in Appendix A. A deeper understanding of cure shrinkage mechanisms is critical to LMAT in order to design manufacturing processes and tooling for compoistes with high dimensional tolerances. This project will provide the required understanding of material behaviour by combining physical testing and numerical simulation to find the best method of measuring cure shrinkage induced strains and stresses. A successful outcome to the project will help to maintain and enhance the UK's position at the forefront of composites manufacture.