The determination of mechanical and fracture properties of anisotropic tubular materials along hoop direction needs the use of the ring hoop tensile test, for which, the obtained results are deceived by the effect of friction between the ring sample and the D-shaped block mandrel. Commonly, lubricants are applied to reduce the friction, which are inefficient in some specific cases; despite of that, it was noticed that scarce works have focused on the development of new mechanical mandrel designs or trying to improve the current ones to resolve the friction concern. The aim of this research is to correctly address the friction issue between the ring sample and the fixture mandrel to significantly reduce its effect on the ring hoop tensile test results without using any kind of lubricants. New mechanical design of D-shaped block mandrels are developed to carry out ring hoop tensile tests to simply characterize the mechanical behaviour of tubular materials. New mechanical D-shaped block mandrels were designed, manufactured and used to carry out experimental ring hoop tensile tests. An inverse identification method based on an artificial neural network trained by finite element simulation responses, was developed to efficiently segregate the flow stress curve from the influence of the friction, inherent in the global force-displacement curve for the classical ring hoop tensile test. The experimental force – displacement curves using five mandrel-types are established and quantitatively compared on the base of their ability to reduce the friction issue. The analysis of the finite element simulations, related to the investigation of the influence of the friction on the ring hoop tensile test results, shows that one of the new developed mandrels reduces the friction coefficient by about 10 times compared to that identified using the classical D-shaped block mandrel. It has been found that, the finite element simulation of ring hoop tensile test using the identified material parameters matches the experimental results. This investigation provides a useful fixture mandrel, which is able to drastically reduce the friction without resort to any lubricants to just determine the material flow stress curve using ring hoop tensile test, regardless the friction level between the sample and mandrel.

确定各向异性管状材料沿环向的力学性能和断裂性能需要使用环环拉伸试验，为此，通过环样品与D形块心轴之间的摩擦作用来欺骗获得的结果。通常，使用润滑剂来减少摩擦，这在某些特定情况下效率不高；尽管如此，人们注意到，稀少的工作集中在开发新的机械心轴设计或试图改进当前的设计以解决摩擦问题。这项研究的目的是正确解决环形样品与夹具心轴之间的摩擦问题，从而在不使用任何润滑剂的情况下，显着降低其对环形箍拉伸试验结果的影响。开发了D形块型心轴的新机械设计，以进行环箍拉伸试验，以简单地表征管状材料的机械性能。设计，制造了新的机械D形块型心轴，并用于进行实验环箍拉伸试验。开发了一种基于人工神经网络的逆识别方法，该方法通过有限元模拟响应训练，可以有效地将流应力曲线与摩擦的影响隔离开，这是经典环箍拉伸试验的整体力-位移曲线所固有的。建立了使用五种心轴类型的实验力-位移曲线，并根据它们减少摩擦问题的能力进行了定量比较。有限元模拟分析 与研究摩擦对环箍拉伸试验结果的影响相关的研究表明，与使用传统D形块型心轴确定的摩擦系数相比，一种新开发的心轴将摩擦系数降低了约10倍。已经发现，使用确定的材料参数进行的环箍拉伸试验的有限元模拟与实验结果相匹配。这项研究提供了一种有用的夹具心轴，无论样品和心轴之间的摩擦水平如何，它都可以大幅度减少摩擦，而无需借助任何润滑剂即可通过环箍拉伸试验来确定材料的流动应力曲线。结果表明，与使用经典D形块型心轴确定的摩擦系数相比，其中一种新开发的心轴将摩擦系数减小了约10倍。已经发现，使用确定的材料参数进行的环箍拉伸试验的有限元模拟与实验结果相匹配。这项研究提供了一种有用的夹具心轴，无论样品和心轴之间的摩擦水平如何，它都可以大幅度减少摩擦，而无需借助任何润滑剂即可通过环箍拉伸试验来确定材料的流动应力曲线。结果表明，与使用经典D形块型心轴确定的摩擦系数相比，其中一种新开发的心轴将摩擦系数减小了约10倍。已经发现，使用确定的材料参数进行的环箍拉伸试验的有限元模拟与实验结果相匹配。这项研究提供了一种有用的夹具心轴，无论样品和心轴之间的摩擦水平如何，它都可以大幅度减少摩擦，而无需借助任何润滑剂即可通过环箍拉伸试验来确定材料的流动应力曲线。