A finite-strain viscoelastic-damage numerical model for time-dependent failure and instability of rocks

2022 ◽  
Vol 143 ◽  
pp. 104596
Xiaofeng Cheng ◽  
Chunan Tang ◽  
Duanyang Zhuang
2020 ◽  
Kanthasamy Ubamanyu ◽  
Daniele Ghedalia ◽  
Armanj D. Hasanyan ◽  
Sergio Pellegrino

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.

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3594
Andrea Sellitto ◽  
Francesco Di Caprio ◽  
Michele Guida ◽  
Salvatore Saputo ◽  
Aniello Riccio

This work is focused on the investigation of the structural behavior of a composite floor beam, located in the cargo zone of a civil aircraft, subjected to cyclical low-frequency compressive loads with different amplitudes. In the first stage, the numerical models able to correctly simulate the investigated phenomenon have been defined. Different analyses have been performed, aimed to an exhaustive evaluation of the structural behavior of the test article. In particular, implicit and explicit analyses have been considered to preliminary assess the capabilities of the numerical model. Then, explicit non-linear analyses under time-dependent loads have been considered, to predict the behavior of the composite structure under cyclic loading conditions. According to the present investigation, low-frequency cyclic loads with peak values lower than the static buckling load value are not capable of triggering significant instability.

1976 ◽  
Vol 98 (2) ◽  
pp. 140-145 ◽  
S. R. Bodner ◽  
U. S. Lindholm

A criterion for the time-dependent failure of materials is developed based upon the concept that failure results from an incremental accumulation of damage. The failure criterion is thereby explicitly tied to the incremental flow law describing the inelastic deformations. The damage increment is assumed as a product of functions of the stored strain energy due to inelastic deformations, the mean hydrostatic stress, and the damage itself. The consequences of the failure criterion for various types of loading are discussed.

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