Strain field inhomogeneities and stiffness changes in GMT containing voids
2002 (English)In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, Vol. 33, no 1, 75-85 p.Article in journal (Refereed) Published
During compression moulding of glass mat thermoplastics (GMT), voids may form. However, it is not clear whether voids are as critical to mechanical performance in GMT as in thermoset composites. The present investigation also considers the general problem of damage mechanisms in GMT. Conventional tensile tests, acoustic emission, a stiffness degradation test and a speckle technique for strain field measurements are used as well as optical microscopy of polished cross-sections. The void content (up to 5%) does not significantly influence the strength or stiffness degradation process. The reason is the large inhomogeneity of the strain fields in GMT. Failure occurs in locally soft regions and void effects are of secondary importance. Details of the failure process are discussed, emphasising the large local strains in matrix-rich regions.
Place, publisher, year, edition, pages
2002. Vol. 33, no 1, 75-85 p.
damage tolerance, mechanical properties, compression moulding, speckle photography, electronic speckle photography, mat-reinforced polypropylene, damage mechanisms, glass, displacement, composites, fracture
IdentifiersURN: urn:nbn:se:kth:diva-21087ISI: 000172089300008OAI: oai:DiVA.org:kth-21087DiVA: diva2:339784
QC 201005252010-08-102010-08-10Bibliographically approved