中文摘要：

针对柔性套管约束杆件，研究了轴压杆件与约束杆件点、线接触时的约束屈曲．在小挠度变形假设下，根据轴压杆件与约束杆件满足变形协调条件的二阶平衡微分方程，推导了轴压杆件挠度、轴向位移、接触反力的计算公式，并且由轴向压力唯一确定了线接触的长度．算例分析表明：当约束杆件刚度较小时，轴压杆件弯曲产生的轴向位移较大；当约束杆件刚度较大时，轴压杆件弯曲产生的轴向位移较小，该轴向位移与文献中的大挠度解吻合很好，从而得出小挠度变形假设是合理的．

英文摘要：

The buckling of an axially compressive strut constrained by a flexible sleeve is studied for the cases of a single point contact and a curved line contact between the strut and the sleeve. Under the small deflection assumption, the second order differential equilibrium equations of the strut and the sleeve satisfying deformation compatibility conditions are obtained. The deflection, the axial displacement, and the contact reactions of the strut are then obtained. The length of the line contact is uniquely determined by the axially compressive force. Two examples indicate that the axial displacement of the strut caused by bending is large when the stiffness of the sleeve is small, and vice versa, which is in good agreement with the large deflection solution. It is confirmed that the small deflection assumption is valid here.