Probabilistic characterization of the effect of transient stochastic loads on the fatigue-crack nucleation time

10/13/2020
by   Stephen Guth, et al.
0

The rainflow counting algorithm for material fatigue is both simple to implement and extraordinarily successful for predicting material failure times. However, it neglects memory effects and time-ordering dependence, and therefore runs into difficulties dealing with highly intermittent or transient stochastic loads with heavy tailed distributions. Such loads appear frequently in a wide range of applications in ocean and mechanical engineering, such as wind turbines and offshore structures. In this work we employ the Serebrinsky-Ortiz cohesive envelope model for material fatigue to characterize the effects of load intermittency on the fatigue-crack nucleation time. We first formulate efficient numerical integration schemes, which allow for the direct characterization of the fatigue life in terms of any given load time-series. Subsequently, we consider the case of stochastic intermittent loads with given statistical characteristics. To overcome the need for expensive Monte-Carlo simulations, we formulate the fatigue life as an up-crossing problem of the coherent envelope. Assuming statistical independence for the large intermittent spikes and using probabilistic arguments we derive closed expressions for the up-crossing properties of the coherent envelope and obtain analytical approximations for the probability mass function of the failure time. The analytical expressions are derived directly in terms of the probability density function of the load, as well as the coherent envelope. We examine the accuracy of the analytical approximations and compare the predicted failure time with the standard rainflow algorithm for various loads. Finally, we use the analytical expressions to examine the robustness of the derived probability distribution for the failure time with respect to the coherent envelope geometrical properties.

READ FULL TEXT
research
05/20/2022

Probabilistic failure mechanisms via Monte Carlo simulations of complex microstructures

A probabilistic approach to phase-field brittle and ductile fracture wit...
research
08/09/2018

On Physical Layer Security over Fox's H-Function Wiretap Fading Channels

Most of the well-known fading distributions, if not all of them, could b...
research
04/20/2023

New Closed-Form ASER Expressions for Dual-Hop Mixed THz-RF Cooperative Relay Networks

In this paper, we consider a dual-hop mixed THz-RF system model for back...
research
03/22/2019

A Comprehensive Performance Evaluation of a DF-Based Multi-Hop System Over α-κ-μ and α-κ-μ-Extreme Fading Channels

In this work, an integrated performance evaluation of a decode-and-forwa...
research
05/10/2023

Generalized Stratified Sampling for Efficient Reliability Assessment of Structures Against Natural Hazards

Performance-based engineering for natural hazards facilitates the design...
research
10/27/2022

Closed-form modeling of neuronal spike train statistics using multivariate Hawkes cumulants

We derive exact analytical expressions for the cumulants of any orders o...
research
02/18/2023

Probabilistic model for spatially acquiring optical links in space under influence of band-limited beam jitter

An analytical model is derived for the probability of failure (P-fail) t...

Please sign up or login with your details

Forgot password? Click here to reset