Optimization of Weld Nut Geometry by Simulation

Sammanfattning: This project covers resistance projectionwelding of HP weld nuts and simulationsof these weld nuts welded to Dogal(350YP, 600DP, 800DP) and HyTens1000. When the simulation results werecompared to results in the previous report,Resistance Nut Welding of High StrengthSteel, it showed that the simulations ofHPM8 weld nuts were more accurate thenthe HPM6 simulations.Comparison HPM8 weld nut welded againstDogal 600DPTherefore projection geometry of theHPM8 weld nuts was selected foroptimisation in this project. Most of thesimulation results were insufficient but insome of the evaluated cases a satisfactoryweld zone was developed.These geometries were manufactured byturning (modifying) existing weld nuts andthen welded with an MFDC weldingmachine. Cross-sections of these weld nutswere compared to the simulation results.These results showed differences in thefusion zone between simulated results andwelding results. The differences were moreconnected to which base material that wasindicates problems in the material modelsComparisons optimized weld nuts of HPM8 typewelded against Dogal 600DP and HyTens 1000Mechanical testing in terms of pull-out andtorsion tests were also carried out. Themaximum pull-out loads were notsignificantly changed compared to theoriginal design. The torsion test methodthat was used was insufficient. The HPweld nuts joint were too strong to be testedwith manual tools and must be tested withmachine testing as a report done by RezaKhezri suggests.The simulation programme that wasevaluated, SORPAS version 9.0 and 9.8,showed to be an insufficient tool forevaluating and optimisation of nutwelding.