Fatigue Characteristic and Weibull Analysis of Sustainable Rubberwood Flour/Recycled Polypropylene Composites

Although there is a perpetual interest in natural fibre composite, the fatigue data and their durability behaviour is still lacking, thus limiting their potential use in high-end applications. In this study, wood polymer composite made from rubberwood flour and recycled polypropylene was subjected to a tension-tension fatigue test in order to investigate their fatigue characteristic. Hysteresis loop was captured in order to establish their stress to number of failure (S-N) curve. The fatigue strength of the composite strongly depends on the stress amplitude. At the lowest stress level, the fatigue life of the composite exceeds the 1.5 million cycles limit, suggesting that the endurance limit for composite materials to be 11.06 MPa. The residual modulus and energy dissipated are plotted as a function of number of fatigue cycles. As the cycles progress, the residual modulus fall and dissipated energy increase indicated the cyclic damage in the composite structure. Two parameters Weibull probability were used to statically analyse the fatigue life and reliability of the rubberwood/recycled polypropylene composite. The S-N curve was plotted at different reliability index (RI = 0.1, 0.368, 0.5, 0.9, 0.99) using Weibull data. This data is used to identify the first failure time and design limits of the materials.

Literature Review on Fatigue Life Analysis of Railway Track Incorporating Effect of Load Sequence

As the railways are the prime mode of transportation, it is extensive to concentrate on railways which increase the economic growth of the country. Considering that the railway traffic system has an enormous influence on the people, the strength reliability of those components is a very important matter related to the safety and safety of the people. As for the strength reliability, one amongst the important study themes is that the strength or fatigue characteristic of every railway component that's subject to repeated loads during use. The reason why it is necessary to consider the fatigue characteristic carefully is that fatigue is a microscopic fracture caused by the initiation and propagation of a crack due to a cyclic slip deformation of the scale of single grain, that fatigue occurs even under a stress smaller than the strength characteristic under a static load (e.g., tensile strength), which it can suddenly result in a fatal fracture without causing any macroscopic plastic deformation and also causes derailment. The literature survey carried out talks about the ideal model for studying dynamic response of railway track, linear and non-linear approaches to find the fatigue life of railway track, crack initiation and propagation, inspection interval for cracks. The literature survey carried out in this paper gives a fair idea about the research gap and thus motivates researchers to carry out future research on the gap found. Keywords: Fatigue life, shear springs, dampers, literature survey, Rain-flow counting method, non-linear damage accumulation, linear mechanics approach, head checks crack and squat crack.

Fatigue monitoring of climbing ropes

Safety improvements in mountaineering gear have enabled the increasing popularity of rock climbing as a sport. Both amateurs and experts want to know the condition of their equipment with a high degree of reliability. For climbing ropes, diagnostics are only carried out qualitatively by visual inspection. The assessment is left to the personal judgment of the user, thus leaving considerable margins of uncertainty on the rope’s condition. To address this shortcoming, this article explores the possibility of estimating fatigue damage from the impact force on the rope. This value is estimated from the measurements of the climber’s acceleration using a wearable device. Then, force data are correlated to the fatigue characteristic of the rope. In this study, three ropes were used by professional climbers through different routes. After this field conditioning, the ropes were tested following the UIAA standard and compared to a control rope. The results show that the proposed method can estimate the rope cumulative damage, but it relies on the accuracy of the damage model. In particular, the parameter describing the contact between the rope and the runner is important for a correct estimate.

An Entropy-Based Neighborhood Rough Set and PSO-SVRM Model for Fatigue Life Prediction of Titanium Alloy Welded Joints

In order to obtain comprehensive assessment of the factors influencing fatigue life and to further improve the accuracy of fatigue life prediction of welded joints, soft computing methods, including entropy-based neighborhood rough set reduction algorithm, the particle swarm optimization (PSO) algorithm and support vector regression machine (SVRM) are combined to construct a fatigue life prediction model of titanium alloy welded joints. By using an entropy-based neighborhood rough set reduction algorithm, the influencing factors of the fatigue life of titanium alloy welded joints such as joint type, plate thickness, etc. are analyzed and the reduction results are obtained. Fatigue characteristic domains are proposed and determined subsequently according to the reduction results. The PSO-SVRM model for fatigue life prediction of titanium alloy welded joints is established in the suggested fatigue characteristic domains. Experimental results show that by taking into account the impact of joint type, the PSO-SVRM model could better predict the fatigue life of titanium alloy welded joints. The PSO-SVRM model indicates the relationship between fatigue life and fatigue life influencing factors in multidimensional space compared with the conventional least-square S-N curve fitting method, it could predict the fatigue life of the titanium alloy welded joints more accurately thus helps to the reliability design of the structure.