Investigation of consolidation of stacked prepreg during robot forming
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
The purpose of this thesis was to investigate consolidation performed robotically of stacked epoxy pre-impregnated carbon ber. Consolidation is when the composite is compacted by applying pressure. This removes voids in the composite which increases mechanical properties. The process of consolidation is generally assumed to be viscoelastic. Two tests were made to investigate the viscoelastic properties of the uncured composite material: One relaxation test to investigate how temperature, stacking sequence, strain level and sample size a ects timedependent viscoelastic properties. The second experiment was to study the level of compaction achieved from local consolidation of the composite material, the latter obtained when using an industrial robot. The relaxation test showed that the compression response was decreased with higher temperatures and increased with higher strain levels. Samples with a reduced area showed larger relaxation e ects than unreduced samples. Unidirectionally stacked samples had larger relaxation e ects than samples stacked cross-directionally. The experiment with robotically applied consolidation did not show any measurable compaction at the pressure levels investigated. The lack of compaction is assumed to be caused by shearing of the upper layers due to high tool friction and that the applied pressures were not high enough to noticeably deform the composite material.
Place, publisher, year, edition, pages
2014. , 18 p.
TRITA-AVE, ISSN 1651-7660 ; 2014:68
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-164291OAI: oai:DiVA.org:kth-164291DiVA: diva2:805309