针对传统预紧组合结构机架预紧力计算模型的不足,以承载下立柱上端内侧角点处的压应力等于零为临界开缝判据,在给定预紧力下,建立综合考虑弯曲和拉压变形的液压机上限载荷的计算模型,结合平衡和变形协调条件,推导出了典型预紧组合结构液压机承受中心载荷时上限载荷的计算公式,并以某厂的120MN大型自由锻造液压机本体为原型,设计并制备了1:15的金属模型压机,利用该模型压机对所提出的计算模型进行了实验验证.实验结果表明,该计算模型是准确可靠的,较传统理论的计算精度有大幅提高.%Aiming at the defects of traditional calculation model of the pre-tightened assembled structure,a critical criterion was proposed that the stress of inside corner at the top of upright column was equal to zero. Then a calculation model considering bending, tension and compression deformation was established under the given pre-tightened force. Combining with the force balance and deformation coordination conditions,the formula of upper limit load was derived,when the typical pre-tightened assembled structure hydraulic press was under the center load. Taking a 120MN heavy free forging hydraulic press as the prototype,a metal model press by the ratio of 1 : 15 was made to verify the proposed model. The experimental results demonstrate that the model established herein is accurate and reliable,there is a substantial increase in the accuracy than that by the traditional one.
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