Topology optimization for infinite fatigue life of cyclic symmetric structures subjected to non-proportional loading

This paper presents a density based topology optimization method for infinite fatigue life constraints of non-proportional load cases, with a specific focus on parts with cyclic symmetry. Considering non-proportional loads in topology optimization significantly broadens the types of design problems that can be handled. The method estimates...

Simulating quasi-brittle failure in structures using Sequentially Linear Methods: Studies on non-proportional loading, constitutive modelling, and computational efficiency

Sequentially Linear Analysis (SLA) is a proven robust alternative to incremental-iterative solution methods in nonlinear finite element analysis (NLFEA) of quasi-brittle specimen. The core of the method is in its departure from a load, displacement or arc-length driven incremental approach (aided by internal iterations to establish equilibrium)...

On the assessment of multiaxial fatigue resistance of welded steel joints in marine structures when exposed to non-proportional constant amplitude loading

Structural geometry and stochastic loads such as swell and wind seas can typically induce multiaxial stress states in welded details of marine structures. It is known that such complex time varying stress states determine the fatigue resistance of welded steel joints. Therefore, it is of importance to account for them in fatigue lifetime...

Non-proportional loading in sequentially linear solution procedures for quasi-brittle fracture: A comparison and perspective on the mechanism of stress redistribution

Sequentially linear solution procedures provide a robust alternative to their traditional incremental-iterative counterparts for finite element simulation of quasi-brittle materials. Sequentially linear analysis (SLA), one such non-incremental (total) approach, has been extended to non-proportional loading situations in the past few years....

Non-proportional loading in sequentially linear analysis for 3D stress states

Sequentially linear analysis (SLA), a non-incremental-iterative approach towards finite element simulation of quasi-brittle materials, is based on sequentially identifying a critical integration point in the model, to reduce its strength and stiffness, and the associated critical load multiplier (λ _crit ), to scale the linear...

Sequentially linear analysis for simulating brittle failure

The numerical simulation of brittle failure at structural level with nonlinear finite<br/>element analysis (NLFEA) remains a challenge due to robustness issues. We attribute these problems to the dimensions of real-world structures combined with softening behavior and negative tangent stiffness at local level which may lead to non-convergence, i...

Algorithm for Non-proportional Loading in Sequentially Linear Analysis

Sequentially linear analysis (SLA) is an alternative to the Newton-Raphson method for analyzing the nonlinear behavior of reinforced concrete and masonry structures. In this paper SLA is extended to load cases that are applied one after the other, for example first dead load and then wind load. It is shown that every nonlinear analysis step can...

Comparative study of multiaxial fatigue methods applied to welded joints in marine structures

Marine structures are particularly prone to action of waves, winds and currents with stochastically varying composition, intensities and directions. Therefore, resultant stresses may cause multiaxial fatigue in specific welded structural details. For the assessment of multiaxial fatigue in welded joints, a wide variety of methods have been...

Modifying Resonance Modes of Dissipative Structures using Magnitude and Phase Information

Several Flapping Wing Micro Air Vehicle (FWMAV) designs exploit structural resonance to decrease power consumption. Practical use of most resonating structures requires temporary modifications to the resonance mode (i.e., the eigensolution). This paper presents a systematic design approach to modify non-proportionally damped resonance modes in a...

Sequentially linear analysis of masonry structures under nonproportional loading