Experimental study on structures with flaws under impact loading

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Journal of Vibration and Shock ›› 2016, Vol. 35 ›› Issue (15) : 103-108.

YANG Ren-shu1,2, DING Chen-xi1, YANG Li-yun1, CHEN Cheng1, SUN Jin-chao1

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Abstract

Using the test system of digital laser dynamic caustics (DLDC) and experimental impacting platform of drop hammer, hole and crack flaws were brought into one experimental research system with single variable of curvature. Dynamic three point bending test of strip PMMA specimens with different flaws under impact loading was studied. Fracture failure experienced three stages: crack initiation and propagation at bottom border of specimens duo to impact stress wave during initial stage; stress release and crack stagnation at flaws during medium stage; crack initiation at top tips of flaws and running through specimens duo to the weight of drop hammer during ultimate stage. Under the same test condition, changes of curvature at flaw tips almost had no effect on crack initiation and propagation during initial stage; stagnation time became shorter with curvature increasing at flaw tips during medium stage, proximate functional relationship between the two was obtained; the stress intensity factors of crack initiation at flaw tips decreased first and then increased with the curvature increasing within limits during ultimate stage.

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dynamic caustics / impact loading / flaw / curvature / stress intensity factor

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YANG Ren-shu1,2, DING Chen-xi1, YANG Li-yun1, CHEN Cheng1, SUN Jin-chao1. Experimental study on structures with flaws under impact loading[J]. Journal of Vibration and Shock, 2016, 35(15): 103-108

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