Fatigue strength of laser-welded foam-filled steel sandwich beams

Anssi Karttunen, Mikko Kanerva, Darko Frank, Jani Romanoff, Heikki Remes, Jasmin Jelovica, Sven Bossuyt, Essi Sarlin

Research output: Contribution to journalArticleScientificpeer-review

13 Citations (Scopus)

Abstract

Laser stake-welded steel sandwich panels are widely used in engineering due to their high stiffness-to-weight ratios. The welds are thinner than the plates they join so that there are two crack-like notches on each side of a weld. As a consequence, the welded joints are susceptible to fatigue. In this study, as a remedy to the fatigue problem, low-density H80-grade Divinycell polyvinylchloride foam is bonded adhesively to the voids of stake-welded web-core sandwich beams. The foam reduces shear-induced stresses in the stake-welds. The choice of Divinycell H80 is founded on earlier J-integral-based finite element fatigue assessments of sandwich panels. Empty and the H80-filled sandwich beams are tested in three-point-bending for stiffness, ultimate strength and fatigue (load ratio R = 0.05). The failure modes in the weld joint region are studied using scanning electron microscopy. The experimental results show that the filling increases the stiffness of the sandwich beams by a factor of three while the weight is increased only by 6%. The ultimate strength is increased by 2.7 times. As for the fatigue behavior, the slope increases from m = 4.508 of empty panels to m = 7.321 of filled panels while the load level at 2 million cycles increases by a factor of 8.5. © 2016 Elsevier Ltd
Original languageEnglish
Pages (from-to)64-72
JournalMaterials and Design
Volume115
DOIs
Publication statusPublished - 5 Feb 2017
MoE publication typeA1 Journal article-refereed

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