Influence of operating parameters on the fatigue life of materials: a combined experimental and statistical study

Today, material fatigue is a crucial area of modern engineering because it has a major impact on the durability and reliability of mechanical components in many industrial systems. The understanding of fatigue mechanisms and their behaviour under different operating conditions is essential for the design of robust and durable systems. This experimental study focuses on the fatigue behaviour resulting from rotational bending of nationally produced materials. The main elements are the determination of the fatigue limit for a given fatigue cycle and the endurance limit. To characterise the fatigue resistance of the material by testing a group of identical specimens subjected to cycles of a given shape. To study the effect of three operational variables, namely hardness (H), surface roughness (Ra) and applied stress (σ), on the response under investigation, i.e. the life of the specimen (number of cycles), experiments were carried out using a Taguchi L18 mixed experimental set. Finally, the results obtained were statistically analysed using analysis of variance (ANOVA) and response surface methodology (RSM). From the experimental results and the analyses carried out, the results show that the applied stress is the statistically most dominant factor on specimen fatigue (life) with a contribution of 38.53%, followed by the stiffness factor with a contribution of 32.81%. Finally, based on the Taguchi method and the Response Surface Model (RSM) developed, it is judged that the higher value obtained for the coefficient of determination (over 80%) clearly shows the strong correlation between predicted and experimental data.