き裂伝ぱ条件による不飽和ポリエステル樹脂破面模様の比較とその変化

概要

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The conditions for crack propagation were varied from a constant load (or stress) condition to a constant elongation (or strain) condition while increasing a central crack length (2Co_1) from 6mm to 200mm in thin sheet plastic (Unsaturated Polyester Resin) specimens of 240mm width (2W), which were fractured under tension at room temperature. Numbers and various dimensions of fracture surface marks of both end close type (abbreviated BECM) and one end opened type (abbreviated OEOM) were measured under optical and scanning electron microscopes and analyzed. The marks observed in specimens fractured under a constant strain condition are excellently approximated by the equation of fracture marks proposed previously by us. Fracture strength and average values of their dimensions for each crack length decrease in a hyperbolic curve similar to the relative crack propagation distance at fracture W/Co_1 as the crack length increases. The experimental results for specimens having Co_1≒5.1mm, 23.85mm and 58.42mm are compared. Their dimensions and their gradients decrease as the length of the primary crack increases, and all these relations are predicted well by the equation of fracture marks.
一般社団法人日本機械学会の論文
1987-07-25