Robust shape optimization of notches for fatigue-life extension

McDonald, Marcus; Heller, Manfred

doi:10.1007/s00158-004-0437-5

Cited by 17 publications

(6 citation statements)

References 22 publications

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“…Robustness of optimal shapes is an issue of practical importance and has been investigated in some detail. For example, in prior investigations [32,35], it is shown that for a fixed minimum radius of curvature constraint, there is a linear increase in peak stress, with increasing values of the angular change in the orientation of the applied stress for typical optimal holes. Also as expected, for a fixed angular misalignment, the stresses increase with decreasing values of the minimum radius of curvature constraint.…”

Section: Analysis and Results For Robust Optimal Shapesmentioning

confidence: 99%

Optimal free-form shapes for holes in flat plates under uniaxial and biaxial loading

Burchill

Heller

2004

The Journal of Strain Analysis for Engineering Design

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This paper presents new and transferable design data defining precise optimal free-form shapes for holes in large and finite width plates under biaxial and uniaxial loading conditions respectively. An iterative two-dimensional finite element gradientless shape optimization procedure was used to obtain the optimal shapes, which offer the lowest possible stress concentration, subject to geometric constraints. Precise non-dimensional coordinates are given for a range of hole aspect ratios and are presented in tabular form that allows them to be easily used by designers. The optimal shapes were determined both with and without minimum radius of curvature constraints. Optimal shapes in large plates were found to provide up to a 28 per cent reduction in peak local stress over elliptical shapes of the same aspect ratio. For finite width plates the reduction in peak local stress was as high as 44 per cent. The results obtained are applicable to both the initial design of components with cut-outs and the shape reworking of existing components to remove damage.

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Section: Analysis and Results For Robust Optimal Shapesmentioning

confidence: 99%

Optimal free-form shapes for holes in flat plates under uniaxial and biaxial loading

Burchill

Heller

2004

The Journal of Strain Analysis for Engineering Design

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“…(1) are fixed (or known) a traditional optimization procedure can be proposed considering the loading trajectory in time along with a suitable multiaxial fatigue criteria [11,12]. On the other hand, whenever uncertainties are present in either r l or r a l (t), more elaborate strategies are required including, for instance, a statistical treatment of the applicable loadings [8].…”

Section: Loading Representation and Problem Formulationmentioning

confidence: 99%

Robust high-cycle fatigue stress threshold optimization under uncertain loadings

Faria

2012

Lat. Am. j. solids struct.

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This paper proposes a strategy to achieve robust optimization of structures against high-cycle fatigue when a potentially large number of uncertain load cases are considered. The strategy is heavily based on a convexity property of some of the most commonly used high-cycle design criteria. The convexity property is rigorously proven for the Crossland fatigue criterion. The proof uses a perturbation technique and involves the principal stress components and analytical expressions for the applicable fatigue criteria. The multiplicity of load cases is treated using load ratios which are bounded but are otherwise free to vary within certain limits. The strategy is applied to a notched plate subject to traditional normal and shear loadings that possess uncertain or unspecified components.

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“…Thus, the robust design optimization (RDO), which enables to reduce the scatter of the structural performance and improve structural safety in a probabilistic manner of risk assessment without eliminating the source of variability, has drawn increasing attention for solving real-world fatigue problems recently. For example, McDonald and Heller [19] incorporated robust design strategies to develop an iterative 2D finite-element-based optimization procedure, which was used to determine precise shape of a hole in a plate to maximize its fatigue life. Li et al [20] presented robust optimization of structural fatigue life based upon stochastic finite element method, aiming to reduce the scatter of fatigue life.…”

Section: Introductionmentioning

confidence: 99%