PS哑铃形试样拉伸性能的影响因素及断裂位置研究

Study on the Influencing Factors and Fracture Location in Tensile Property of PS Dumb-bell Specimens

利用自行研制的不溢式压模,制备了不同过渡段结构的PS哑铃形压制试样。通过冲击实验和偏光显微镜观察分析了试样的微观形态,研究了试样不同过渡段结构以及应力集中对拉伸强度的影响,并统计了拉伸断裂位置。研究结果表明:不同过渡段结构的哑铃形压制试样聚集态结构是均质的;拉伸强度随拉伸速率和过渡段圆弧半径的增大而增大;应用应力集中系数修正公式计算拉伸强度更接近材料的真实强度。分析结果表明,哑铃形试样拉伸断裂位置发生在距平直段与过渡段切点1～3mm的应力集中区域。

The dumb-bell pressing specimens with the different transitionary structures Were prepared by using serf-made positive compression mold. The micro morphology was analyzed by the impact test and polarizing microscope, studied the influence of the different transitionary structure and stress concentration on the tensile strength, and the tensile fracture locations were counted. The results showed that the aggregation structure of the dumb-bell pressing specimens with different transitionary structures was homogeneous, the tensile strength increased with the enlargement of tensile rate and arc radius, and applied the stress concentration factor to correct the formula, the tensile strength was closer to the true one of materials. The analyticai results indicated that tensile fracture location of the dumb-bell pressing specimens were in the stress concentration domain which was near the cut point of the straight section and the transitionary circular were 1 - 3 mm.