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Recombinant bamboo is one of the commonly used natural fiber-reinforced composite materials in modern engineering. In this paper, the short-term tensile creep behavior of this material was studied. First, the standard tensile fracture experiments were conducted on nine species to provide the basic strength parameter. Then, six groups of tensile creep experiments were carried out based on the different stress levels. Finally, different viscoelasticity constitutive models were chosen to fit the strain–time relationship obtained by the experiment. The fitting results showed that the traditional generalized constitutive Kelvin viscoelasticity model can express the short-term creep behavior of the recombinant bamboo under high stress levels but will result in some errors in analyzing the creep strain history under the low stress levels. While the proposed modified generalized Kelvin model can provide enough accuracy in fitting the time–strain relationship under all stress levels, it is thus more suitable for engineering applications. [ABSTRACT FROM AUTHOR]

In this article, high-cycle bending fatigue limit load prediction of several sets of high-strength steel crankshafts are conducted based on the critical distance (TCD)approach. Firstly, the critical length of the critical distance of the crankshaft is determined by the crack-modeling technique. Then the equivalent stress of the crankshaft is calculated by a combined method of the finite element and interpolation. Finally the fatigue limit load of the crankshaft with the same material but different structure is computed. Validation between the predictions and the experimental results shows that the conventional TCD may result in some errors in such fatigue limit load prediction, especially for the critical point method(the error may be larger than 10%). While the modified TCD proposed in this paper can provide a more satisfactory result in terms of the fatigue limit for a quick engineering prediction and is thus more suitable to be taken into the actual engineering applications. Unlabelled Image • Combination of the finite element analysis and fracture surface observation. • Applying a new critical distance approach in component fatigue limit load prediction. • Experimental verification for several cases and the universality of the conclusion can be improved obviously. [ABSTRACT FROM AUTHOR]

• The remaining life prediction research in the fatigue research field. • A new modification of the sampling range based on the theory of fracture mechanics. • Both predictions and experimental verifications. For the critical engine parts such as the crankshafts, the fatigue property is necessary for the guidance in actual engineering applications. At present, this property is usually evaluated by the standard fatigue experiment, which is time-consuming and expensive. In this paper, an accelerated fatigue experiment method was developed to shorten the period of the crankshaft fatigue experiment. First the residual fatigue life of the crankshaft was predicted based on the particle filtering algorithm method. Then the system state-space equations was modified based on the theory of fracture mechanics to improve the accuracy of the predictions. Finally the statistical analysis based on the predicted data was adopted to determine the fatigue limit load of the crankshaft. The result showed that this method could provide nearly the same statistical analysis result with that obtained from the standard experiment process (the relative difference is less than 2%), and the experiment period was cut down by 20% or more, which makes it feasible for actual engineering applications. [ABSTRACT FROM AUTHOR]

• 3D finite element simulation of the induction hardening process. • Comparative study of different mean stress models in crankshaft fatigue research. • Combination of the mean stress model and multi-axial fatigue. Electromagnetic induction quenching is one of the common surface strengthening approaches conducted engineering application, especially for the steel parts. In this paper, first a 3D finite element model was built and the electromagnetic thermal coupling simulation was used to determine the temperature field after quenching and coolant cooling process. Then the mechanical-thermal coupling simulation was used to obtain the residual stress field remaining in the crankshaft after air cooling. Finally the fatigue property of the treated crankshaft was predicted based on the residual stress and the different mean stress models. Validations between the predictions and the experimental results showed that the combination of the simulation and Goodman model can obtain the fatigue property of this type of crankshaft accurately, thus was suitable for actual engineering applications. [ABSTRACT FROM AUTHOR]

• Comparative study of different critical distance models in crankshaft fatigue research. • Model parameter error influence on the prediction is discussed. For critical engine parts, such as crankshafts, fatigue strength is one of the most important parameters in the design and manufacturing stage. In previous work, fatigue limit loads of the crankshafts with different structural features were predicted based on different theories of critical distance (TCDs). The results showed that the definition of the TCD had an obvious impact on the accuracy of such predictions. This paper, first the critical distance was determined based on the limit stress distribution of a given crankshaft and the definition of the approach. Then, the fatigue limit load of another crankshaft was predicted based on the parameters obtained in the previous step. Finally, corresponding experimental verification and model parameter error influence analysis were conducted to evaluate the accuracies of the predictions. The results showed that for the modified indirect-defined TCD (ITCD), the predictions based on the line and point methods were approximately equal, and the parameter errors had an obvious impact on the predictions. However, for the direct-defined TCD (DTCD), the critical line approach had much better accuracy than the critical point approach, and the DTCD was much less sensitive to the model parameter errors than the ITCD approach, therefore, the DTCD approach is much more suitable for actual engineering applications. [ABSTRACT FROM AUTHOR]