Fatigue strength evaluation of PPGF35 by energy approach during mechanical tests

Thanks to the progress of research on thermoplastic materials, the properties of composite materials have improved considerably. The aim of this study is the evaluation of fatigue strength of glass-fibre-reinforced polypropylene composite (PPGF35) by applying both the Risitano Thermographic Method (RTM) and the new Static Thermographic Method (STM).

An exploratory test of an intuitive evaluation method of perceived argument strength

According to Mercier and Sperber (2009, 2011, 2017), people have an immediate and intuitive feeling about the strength of an argument. These intuitive evaluations are not captured by current evaluation methods of argument strength, yet they could be important to predict the extent to which people accept the claim supported by the argument. In an exploratory study, therefore, a newly developed intuitive evaluation method to assess argument strength was compared to an explicit argument strength evaluation method (the PAS scale; Zhao et al., 2011), on their ability to predict claim acceptance (predictive validity) and on their sensitivity to differences in the manipulated quality of arguments (construct validity). An experimental study showed that the explicit argument strength evaluation performed well on the two validity measures. The intuitive evaluation measure, on the other hand, was not found to be valid. Suggestions for other ways of constructing and testing intuitive evaluation measures are presented.

Fatigue Strength Evaluation of Welded Structure on Aluminum Alloy Car Body Based on Multi-Axial Stress

With the continuous development of the subway, the demand for its safety and stability is getting higher and higher. It is of great significance to accurately evaluate the fatigue life of the carbody to ensure the subway's safe operation. In this paper, the finite element model of a subway head carbody was established, and the fatigue strength of the welded structure on the carbody was evaluated based on Multi-axial stress. The local coordinate system was defined according to the geometrical characteristics of the welds. Local stresses perpendicular and parallel to the weld seam were obtained to calculate the stress ratio, stress range, and allowable stress value corresponding to the stress component. According to the joint fatigue resistance, the components of the degree of utilization and comprehensive degree of utilization are calculated to evaluate the structural fatigue strength under the survival rate of 97.5% and load cycles of 10 7 . The evaluation of the fatigue strength of the pivotal weld joints shows that the fatigue strength of the aluminum alloy carbody meets the design requirements, the weld of the carbody has a strong ability to resist fatigue damage. The fatigue strength of the weld is mainly affected by the normal stress component, while the shear stress has little effect on the fatigue strength of the structure. In addition, compared with the filleted weld joint and the butt-welded joint, the normal stress parallels to and perpendicular to the weld direction and shear stress have the greatest effect on the lap-welded joint. Meanwhile, the comprehensive degree of utilization of the lap-welded joint is the largest at 0.49. The introduction of multi-axial stress for the fatigue strength evaluation is beneficial when considering the material utilization degree in multiple structural directions. This research results provide a reference for fatigue strength evaluation of subway carbody's welded structure.