Failure of Laser Welded Structures Subjected to Multiaxial Loading: Experimental Development

A unique experimental capability was developed so combined mechanical and thermal loads could be imposed on specimens that are representative of laser welded structures. The apparatus, instrumentation and specimens were designed concurrently to yield the ability to apply a wide range of loading conditions that accurately replicate the multiaxial stress states produced in laser welded, sealed structures during pressurization at high temperatures up to 800 °C. Axial, radial and torsional loads can be applied individually or in combination, by direct or variable loading paths, to eventual failure of laser weld specimens. Several advantages exist for applying equivalent stress states by mechanical means rather than pressurization with gas, including: repeatability, controlled failure, safe experiments, assessment of loading path dependence, experimental efficiency and overall facility. The experimental design and development are described along with resulting measurements and findings from sample experiments.