Optimisation of a welded construction

A shape optimisation of a welded component of a VOLVO excavator was performed to increase its service life. The aim of the optimisation was to minimise the risk of crack propagation during operation of the excavator.

A fracture mechanics analysis was performed using our in-house software XCrack and coupled to the optimisation. The objective function was to minimise the stress intensity factors at the modelled cracks in the weld roots. In order to control the shape of the construction within the available design space, 23 independent shape variables where used.

The optimisation resulted in a reduction of the stress intensity factors by 40%, compared to the initial design. This means that the crack will not propagate under service. The modifications of the component where rather small and the component can be manufactured using the same process as before.


By using structural optimisation it is possible to perform fracture mechanics dimensioning efficiently to increase the fatigue life of structures.