Experimental study on fatigue failure and damage of sandwich structure with PMI foam core

Abstract

Sandwich structures consisting of aluminium skin sheets and polymethacrylimide foam core have been gradually used in the high‐speed trains. The static mechanical properties and fatigue damage of the sandwich structures with polymethacrylimide foam core were experimented in three‐point bending and were discussed. The failure mode is identified as local indentation. The static strength was obtained, and it showed good consistency with the forecasting formula. The fatigue property and damage evolution were also researched under cyclic loading. The fatigue life curve and the fitting formula were submitted. The fatigue damage evolution started from the skin sheet fracture and then the foam core indentation. The displacement at the midpoint as the damage parameter was discussed, and the evolution prediction formula was submitted, which showed great agreement with the experimental results.

Acoustic emission description from a damage and failure scenario of rotomoulded polyolefin sandwich structure subjected to internal pressure for storage applications

“…a group for localization according to the 8 sensors: 3D localization (minimum 4 sensors), two groups for each large face (1,2,3,4) and (5,6,7,8): 3D localization but according to a plan (minimum 3 sensors), four groups for each edge (1,2) (3,4) (5,6) (7,8): linear localization (minimum 2 sensors), in order to possibly capture AE events during the tests.…”

“…In the literature, numerous works on these subjects and describing the different structures of materials are presented. Here are just a few of the many works describing the bending characterization [6][7][8][9][10] and falling weight impact test devices that have been reported [11][12][13]. In addition to the knowledge of the mechanical behaviour of these sandwich structures, the structural complexity of these ones requires additional means.…”

Research on rapid preparation and performance of polymethacrylimide foams

“…The PMI foams with different properties were successfully developed by Degussa Co., Ltd. in 1972. In the past decade, the PMI foams had been attracted great attentions due to its outstanding performance, and many researchers carried out deeply investigation on the sandwich construction with PMI foams and PMI foams alone . However, one of the initial raw materials for preparing PMI foams was almost the expensive methacrylonitrile (MAN) in the previously reported works, which resulted in the high cost of PMI foam and inhibited its widely application.…”

Failure mechanism of PMI foam core sandwich beam in bending

“…The fatigue behaviors of the PMI foam in tension, compression and shear were investigated by Burman and Zenkert [5][6][7] as well as the impact responses [8][9][10][11]. In addition, the basic mechanical properties of sandwich structures with PMI foam core were also characterized [5,7,[12][13][14][15][16][17][18][19][20][21][22], where the sandwich beams or panels with PMI foam core have been tested in standard or specialized tests such as shearing [7,14,20], three point bending [16,18,20], four point bending [5,12,14], edgewise compression [20,22] and indentation [17,21]. According to these studies, the foam's density has significant influence on the failure modes of the sandwich structures [17].…”

“…According to these studies, the foam's density has significant influence on the failure modes of the sandwich structures [17]. The most common failure mode of the PMI foam core sandwich structures is core shearing [7,12,13,16,22], followed by local indentation collapse [16][17][18]21] and face yielding [7,22]. However, among these studies, there is a lack of systematical research on the PMI foam core sandwich structures' failure mechanism in terms of the mechanical properties of foam, such as the foam density.…”