PURPOSE: To enable evaluation of a stretcher strain of an offset yield stress material. ;CONSTITUTION: When a first proportional part 1 in the initial stage of measurement and a second proportional part 2 positioned in a region exceeding the proportional limit of the first proportional part 1 are connected by a curve 3 of a differential value 0 or above and a tangent (a) of the minimum differential value on the curve is positioned inside the second proportional part 2, in regard to a load-elongation curve obtained on the occasion when an offset yield stress material is subjected to a tensile test, a difference in an elongation value of which the start point and the end point are points (d) and (e) at which an upward extension (b) of the first proportional part 1 and a downward extension (c) of the second proportional part 2 intersect the tangent (a) respectively is made a pseudo-yield elongation YEL', and based on the pseudo-yield elongation WEL', a stretcher strain is evaluated.;COPYRIGHT: (C)1993,JPO&Japio
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