Composites made of glass fibers and unsaturated polyester resins are widely applied for various products. The failure processes of such composites are insufficiently understood. Fracture of the resin often initiates bulk composite fracture. Residual stresses occur during the curing of the resin due to the resin volumetric shrinkage. These unfavorable stresses may enhance resin fracture. Moreover, resin shnnkage may decrease the surface quality of the product. The addition of Low Profile Additives &PA) to the resin may decrease or even remove these problems. The shrinkage behavior of unsaturated polyester resin with varying amounts of LPA is investigated in this work. The emphasis is on the development of curing shnnkage occurring after the gel point of the resin and on accompanying shnnkage stresses. These stresses can be reduced and even reversed by the addition of LPA.

Interface delamination failure caused by thermomechanical loading and mismatch of thermal expansion coefficients and other material properties is one of the important failure modes occurring in electronic packages, thus a threat for package reliability. To solve this problem, both academic institutions and industry have been spending tremendous research effort in order to understand the inherent failure mechanisms and to develop advanced and reliable experimental and simulation methodologies, thus to be able to predict and to avoid interface delamination before physical prototyping. Various damage mechanisms can be involved and can result in interface delamination phenomena. These are not all sufficiently addressed and/or reported so far, probably because of the complexities caused by the occurrence of strong geometric and materials nonlinearities. One of the phenomena being insufficiently understood so far is the so-called buckling-driven delamination of thin metalic layers on ceramic substrates. This phenomenon will be discussed in the present paper.