ISSN:
1662-8985
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
To quantify the effect of structural through-thickness reinforcement in foam core sandwichcomposite panels, an experimental study was carried out which included three-point bending tests,core shear tests, flatwise tensile and compression tests, as well as edgewise compression tests.Standard test procedures based on ASTM guidelines are followed to test the behavior of the stitchedpanels with reinforcement at 90 degree orientation with respect to the sandwich faces. The testspecimens were manufactured by using polyurethane foam Rohacell 71 IG and carbon fiberreinforced composite facesheets. The dry perform facesheets and foam core were then assembled in adry lay-up already stitched. Kevlar 29 yarn was used to stitch both sets of panels. The results showeda significant effect of the stitching on the in-plane Young’s modulus which was attributed to localdisplacements of the in-plane fibers and changes in the fiber volume fraction. Stitching of sandwichpanels significantly increases the maximum failure loads under flexure, core shear, flatwise tensile,flatwise compression, and edgewise compression loading.A finite element based unit-cell model was developed to estimate the elastic constants ofstructurally stitched foam core sandwich composite panels taking into consideration the yarndiameter, the stitching pattern and direction as well as the load direction. Depending on theseparameters, local changes of the fiber volume fraction as well as regions with undisturbed anddisturbed fiber orientations within the laminate plies are taken into account. A good match betweenthe finite element modeling and the experimental data was obtained. The present work should beconsidered as a step towards developing a more sophisticated numerical model capable ofdescribing mechanical behavior of sandwich structures
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.33-37.477.pdf
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