scholarly journals Two-parameter Failure Model Improves Time-independent and Time-dependent Failure Predictions

2004 ◽  
Author(s):  
R Huddleston
2011 ◽  
Vol 128-129 ◽  
pp. 361-366
Author(s):  
Yan Luo ◽  
Qing Gao

Based on the time-dependent deformation behavior of solder alloy 63Sn-37Pb at room temperature, a damage-coupled unified visco-plastic multi-axial fatigue model and its failure criterion were proposed. In the evolution equation of damage for the model, the time-dependent effect of damage was taken into account. The model was used to predict the fatigue life under different loading paths. The comparison between the predicted and experimental results demonstrated that the time-dependent failure model can simulate the deformation behavior and predict the fatigue life well under different nonproportional strain paths.


Mathematics ◽  
2021 ◽  
Vol 9 (14) ◽  
pp. 1657
Author(s):  
Jochen Merker ◽  
Benjamin Kunsch ◽  
Gregor Schuldt

A nonlinear compartment model generates a semi-process on a simplex and may have an arbitrarily complex dynamical behaviour in the interior of the simplex. Nonetheless, in applications nonlinear compartment models often have a unique asymptotically stable equilibrium attracting all interior points. Further, the convergence to this equilibrium is often wave-like and related to slow dynamics near a second hyperbolic equilibrium on the boundary. We discuss a generic two-parameter bifurcation of this equilibrium at a corner of the simplex, which leads to such dynamics, and explain the wave-like convergence as an artifact of a non-smooth nearby system in C0-topology, where the second equilibrium on the boundary attracts an open interior set of the simplex. As such nearby idealized systems have two disjoint basins of attraction, they are able to show rate-induced tipping in the non-autonomous case of time-dependent parameters, and induce phenomena in the original systems like, e.g., avoiding a wave by quickly varying parameters. Thus, this article reports a quite unexpected path, how rate-induced tipping can occur in nonlinear compartment models.


2020 ◽  
Author(s):  
Kanthasamy Ubamanyu ◽  
Daniele Ghedalia ◽  
Armanj D. Hasanyan ◽  
Sergio Pellegrino

Author(s):  
Khashayar Hojjati-Emami ◽  
Balbir S. Dhillon ◽  
Kouroush Jenab

Nowadays, the human error is usually identified as the conclusive cause of investigations in road accidents. The human although is the person in control of vehicle until the moment of crash but it has to be understood that the human is under continued impact by various factors including road environment, vehicle and human's state, abilities and conduct. The current advances in design of vehicle and roads have been intended to provide drivers with extra comfort with less physical and mental efforts, whereas the fatigue imposed on driver is just being transformed from over-load fatigue to under-load fatigue and boredom. A representational model to illustrate the relationships between design and condition of vehicle and road as well as driver's condition and state on fatigue and the human error leading to accidents has been developed. Thereafter, the stochastic mathematical models based on time-dependent failure rates were developed to make prediction on the road transportation reliability and failure probabilities due to each cause (vehicle, road environment, human due to fatigue, and human due to non fatigue factors). Furthermore, the supportive assessment methodology and models to assess and predict the failure rates of driver due to each category of causes were developed and proposed.


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