A macro-NPR (negative Poisson's ratio) bolt, also called a He bolt, is a composite structure that is composed of two types of steel that are adjusted by design. The mechanical characteristics of the macro-NPR bolt are high constant resistance, large deformation, energy absorption, and impact resistance. In this work, the concepts of a “climbing angle” and a stick-slip element were introduced to analyze the mechanical behavior of the macro-NPR bolt. It was observed that certain bottleneck problems in the existing constitutive model of the macro-NPR bolt had not been solved: (1) The calculation equation of stick-slip displacement included some parameters with weak correlation. (2) In calculating a single stick-slip cycle, the displacement was assumed to be instantaneously completed, whereas the cone sliding process was considered. (3) The random stick-slip phenomenon had a great influence on the performance of the macro-NPR bolt. These problems could lead to significant differences between the existing macro-NPR bolt static tension theoretical curve and the experimental curve. To solve these bottleneck problems, a method to modify the existing constitutive equation of the macro-NPR bolt was proposed in this work, and the modified constitutive equation of the macro-NPR bolt was established to explore the key factors of the macro-NPR bolt to achieve high constant resistance and large deformation characteristics. During static tension, the stress state of the macro-NPR bolt was divided into two stages, an elastic stage and a constant resistance stage. For the constant resistance stage, the stick-slip phenomenon occurred between the cone and the sleeve, whereas the axial force of the macro-NPR bolt was basically constant around P₀. Then, using the theory of elasticity and the climbing angle theory, the stress state of the macro-NPR bolt sleeve during tension was solved, and a mathematical expression of constant resistance of the macro-NPR bolt was obtained. Finally, the modified constitutive equation of the macro-NPR bolt was established through the corresponding expression and stick-slip element.

宏观NPR（负泊松比）螺栓，也称为He螺栓，是一种复合结构，由两种经过设计调整的钢材组成。宏观NPR螺栓的力学特性是恒阻高、变形大，能量吸收和抗冲击性。在这项工作中，引入了“爬升角”和粘滑元件的概念来分析宏观 NPR 螺栓的机械性能。观察到，现有的宏观NPR螺栓本构模型存在一些瓶颈问题没有得到解决：（1）粘滑位移计算方程中包含一些相关性较弱的参数。(2) 在计算单个粘滑循环时，假设位移是瞬时完成的，而考虑了锥体滑动过程。(3)随机粘滑现象对宏观NPR螺栓的性能影响很大。这些问题可能导致现有的宏观 NPR 螺栓静态拉伸理论曲线与实验曲线之间存在显着差异。大变形特性。在静态拉伸过程中，宏观NPR螺栓的应力状态分为两个阶段，弹性阶段和恒阻阶段。对于恒阻阶段，锥体和套筒之间发生粘滑现象，而宏观NPR螺栓的轴向力在P ₀附近基本恒定。然后，利用弹性理论和爬坡角理论，求解了宏观NPR螺栓套筒在拉伸过程中的应力状态，得到了宏观NPR螺栓的恒阻数学表达式。最后，通过相应的表达式和粘滑元素建立了宏观NPR螺栓的修正本构方程。