Improved Fracture Characterization of High Strength Steels due to a new Test Method for Shear Tension Specimen on uniaxial Tensile Testing Machines

单轴拉伸试验机上剪切拉伸试样的新测试方法改善了高强度钢的断裂表征

• 批准号: 405334714
• 负责人: Professor Dr.-Ing. Bernd-Arno Behrens
• 金额: --
• 依托单位: Institut für Umformtechnik und Umformmaschinen (IFUM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/405334714?language=en
• 关键词: Improved; Fracture; Characterization; Strength; Steels

In order to maintain the dominating position of advanced high-strength steels (AHSS) as compared to other lightweight materials in automotive industry, there is a need for continuous development of AHSS as well as a better utilization of their lightweight potential. The numerical analysis of forming processes on basis of FEM provides an effective method to improve this utilization.In contrast to the conventional method for the description of fracture strains in sheet metal forming processes with the help of FLD, stress-based fracture models can be used for forming processes with non-linear strain paths as well as multi-stage forming processes, and furthermore, besides ductile fracture also shear fracture can be predicted. The calibration of stress-based fracture models has not been standardized yet. Therefore, estimated fracture strains of AHSS available in literature often differ much from one author to another because of different testing procedures with varying developments of the stress state in the fracture initiation zone of the specimen. The objective of the project is to develop a procedure for uniaxial tensile testing machines based on shear tension tests, whereby it is possible to calibrate precisely the fracture behaviour of AHSS for a wide range of stress-states. For this purpose, an already developed butterfly specimen will be used and a new test device will be developed. This device will allow adjusting continuously the angle between the specimen and the force direction of the testing machine during the test thus a constant stress state in the specimen can be maintained.

为了与汽车行业的其他轻量级材料相比，为了维持高级高强度钢（AHS）的主导地位，需要持续开发AHSS以及更好地利用其轻质潜力。基于FEM的形成过程的数值分析提供了一种有效的方法来改善这种利用率。与传统方法相反，可以在FLD的帮助下描述钣金形成过程中的断裂菌株，基于压力的断裂模型可用于与非线性应变路径的非线性菌株以及多个阶段的形成过程以及效果的效果相比，将其用于非线性应变路径，以及效果不佳的效果。基于应力的断裂模型的校准尚未标准化。因此，文献中可用的AHS的估计裂缝菌株通常从一个作者到另一个作者差异很大，因为不同的测试程序在标本的裂缝起始区域的压力状态发生了不同的发展。该项目的目的是基于剪切张力测试为单轴拉伸测试机制定程序，从而为广泛的应力态准确地校准AHSS的断裂行为。为此，将使用已经开发的蝴蝶标本，并将开发新的测试设备。该设备将允许在测试过程中连续调整样品和测试机的力方向之间的角度，从而可以保持样品中的恒定应力状态。