Life simulation code#
Life simulation series#
Life simulation crack#

These types of studies were focused on the fatigue reliability in a specimen level and few of them evaluated life scatter in structure level.

Life simulation crack#

It allows to estimate probability density function and cumulative distribution function of fatigue crack growth life under the randomness of the loads, material properties of crack propagation rate, and crack geometries. proposes a novel uncertainty propagation for probabilistic fatigue crack growth life prediction. combined normal and smallest-extreme-value probability density functions to model the life scatter of SвЂ“N curve. used a two-parametric Weibull distribution to model both S-N and E-N curves.

Because Weibull distribution has a more general functional form than normal distribution, Klemenc et al. explored the generalization of the Castillo-Canteli probabilistic fatigue model and utilized it for the structureвЂ™s fatigue life estimation. Other available researches show interest in establishing the lifetime distribution. Prior work on this aspect includes probabilistic modelling of variability in material properties (e.g., elastic modulus, fatigue limit, yield strength), ,, equivalent initial flaw size,, microstructures as well as defects. Therefore, one significant topic with widespread interest is systematically dealing with uncertainty in fatigue design. It affects the robustness of fatigue design. Uncertainty in fatigue leads to a scatter of structural performance. Though this kind of methods are easy to apply, they describe multiple sources of uncertainty empirically, which may result in an over-conservative reliability analysis.Д¬ontinuous efforts have been made to reduce the over-conservatism in the assessment of structureвЂ™ fatigue reliability.

Life simulation code#

In addition, British standard BS 5400: Part 10 and ASME Boiler & Pressure Vessel Design Code also suggest some factors for considering the uncertainty in fatigue failure process. The FKM Guideline prescribes S-N curves of P fВ =В 0.25% with the safety factor ( Оі F = 1.5) for steel and aluminum components. For example, Eurocode 3 suggests designers a safety factor Оі F = 1.35 when adopting the S-N curve for different welded details under 5% failure probability.

Life simulation series#

In generally, some standards/codes in engineering usually employ semi-probabilistic approaches and provide designers a series of safety factors. Therefore, itвЂ™s necessary to perform fatigue reliability analysis for components to ensure safety. However, fatigue life usually exhibits a stochastic behavior in practical engineering because of material variability, manufacturing errors and stochastic load. ItвЂ™s of paramount importance to assess remaining life of these mechanical components in industry. It may result in a catastrophic accident when fatigue failure occurs suddenly.

Currently, mechanical equipment is moving in a large, high performance, complex service environment direction, such as shield tunneling machine, high-speed rail, aero-engine etc. Fatigue failure is a main threat for mechanical structures subject to cyclic loading.