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对双金属复合管单位长度质量的等效截面抗弯曲、抗拉压、抗扭刚度进行了推导。分析了钢-铜、钢-铝双层、铜-钢-铜三层双金属复合管在不同结构和尺寸组合时,其各等效截面刚度与同规格单金属管各截面刚度之比随内层管与总管壁厚之比n的变化规律。获得了最优刚度性能的复合管最佳结构与尺寸组合,能节约贵金属材料。采用等效截面抗弯曲刚度、等效截面抗拉压刚度、等效质量法,推导出双金属复合管弯曲振动和轴向振动固有频率的计算模型;采用等效截面抗扭刚度、等效质量并结合等效转动惯量法,推导出其扭转振动固有频率计算模型。复合管前三阶固有频率的计算值与有限元值相比,最大误差为2.35%;与实测值相比,最大误差为3.15%。研究结果表明:内铝、外钢复合管在抗弯、抗扭方面(n=0.63时)存在最优结构。
The equivalent cross section bending resistance, tensile strength and torsional stiffness of bimetallic composite pipe are deduced. The ratio of the equivalent cross-section stiffness to the cross-section stiffness of single metal pipe with the same gauge is analyzed with the different structure and size combinations of steel-copper, steel-aluminum double-layer and copper- Variation of the ratio of wall thickness n to wall thickness of the pipe. The optimal structure and size combination of the composite pipe with the best stiffness performance can save precious metal materials. The calculation model of flexural vibration and natural frequency of bimetallic composite pipe is deduced with equivalent section bending stiffness, equivalent section tensile strength and equivalent mass method. The torsional stiffness of equivalent section, equivalent mass Combined with the equivalent moment of inertia method, the calculation model of torsional vibration natural frequency is deduced. Compared with the finite element value, the maximum error of the first three orders of natural frequency of the composite pipe is 2.35%. Compared with the measured value, the maximum error is 3.15%. The results show that there is an optimal structure for the inner and outer steel composite pipe in bending and torsion (n = 0.63).