COMPARATIVE ANALYSIS OF ADDITIVELY MANUFACTURED FOAM BEHAVIOR AGAINST ESTABLISHED OPEN-CELLED FOAM MODELS

Abstract

In support of body armor development this thesis uses volumetric, force and displacement data of additively manufactured foam samples in compression studies to compare an existing foam behavior model based on traditionally manufactured foams, the theory of open-celled foams, to additively manufactured foams. Sample volumetric data is observed at consistent strain intervals throughout compression studies, using a custom photogrammetric system and post-processing pipeline. Force and displacement data are obtained by load and displacement sensors respectively. All samples tested are cylindrical, use an array of 2D and 3D internal fill structures, and are manufactured using consumer grade filaments and fused deposition modeling printing systems. It is observed that additively manufactured foams do not follow the expected behavior established by the theory of open-celled foams, but an adapted design ruleset could be created using similar principals by modifying the parameters of the laws within the theory of open-celled foams. Some sample subsets are shown to exhibit a negative Poisson’s Ratio (auxeticness), without the use of specifically designed structures, as is typically required.