On the Strength Characteristics of Bolted Joint with Gasket under Thermal Change

带垫片螺栓连接热变化下的强度特性研究

• 批准号: 63550123
• 负责人: KUMANO Hiroyuki
• 金额: $ 1.34万
• 依托单位: Tokyo Metropolitan Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63550123/
• 关键词: Bolted Joint; Fixing Element; Thermal Change; Spring Constant; Strain Gauge; Gasket; Bolt Axial Force; Hollow Cylinder; Rectangular Plate; ひずみゲージ; 内力係数

This research deals with the characteristics of bolted Joints under thermal changes. When a bolted joint in which the coefficient of linear expansion of bolts is less than that of clamped parts is put under thermal changes, the bolt axial force produced in the bolt and the compression between the clamped parts are increased with an increase of temperature. The variations of the bolt axial force and the compression between the clamped parts are analyzed during an increase of temperature, and a formula to obtain these variations is proposed. In the experiments strain gauges for high temperature are glued to the shank of the bolt made of steel and the outer circumference of the clamped parts made of aluminum. When a bolted joint is put in a furnace, the strains of the bolt and the clamped parts are measured during an increase of temperature. The numerical results are in fairly good agreement with the experimental results.In addition, the characteristics of a bolted joint, in which a rectangular thick plate made of aluminum was fastened at room temperature by a nut and a bolt made of steel, were examined when the joint was subjected to heat conduction. In the experiments, temperature distributions on the plate were measured with thermocouples, and an increment of bolt axial force and the maximum stress produced in the bolt due to the difference of the coefficients of linear expansion were measured by strain gauges for high temperature when one side of the thick plate was beaten and the opposite side was cooled. Using the difference method, the temperature distributions in the plate subjected to the heat conduction were analyzed. A method to obtain an increment of bolt axial force and the maximum stress produced in the bolt was proposed. The analytical results were fairly consistent with the experimental ones.

本文研究了热变化条件下螺栓连接的特性。当螺栓的线膨胀系数小于夹紧件的线膨胀系数时，随着温度的升高，螺栓中产生的螺栓轴向力和夹持件之间的压缩都会增加。分析了螺栓轴向力和夹紧件之间的压力随温度升高的变化规律，提出了计算这些变化的公式。在实验中，高温应变片被粘在钢制螺栓的杆部和铝制夹持件的外周上。当将螺栓连接放入炉子中时，在温度升高期间测量螺栓和夹紧部件的应变。数值计算结果与试验结果吻合较好。此外，还研究了铝制矩形厚板在室温下用螺母和钢制螺栓连接的螺栓连接的热传导特性。在实验中，用热电偶测量了厚板上的温度分布，用高温应变片测量了厚板一侧敲打另一侧冷却时螺栓轴向力的增量和由于线膨胀系数的差异在螺栓内产生的最大应力。用差分法分析了导热作用下平板内的温度分布。提出了一种获得螺栓轴力增量和螺栓产生的最大应力的方法。分析结果与实验结果基本一致。