Combining Variation Simulation With Thermal Expansion Simulation for Geometry Assurance

S. Lorin, L. Lindkvist, R. Söderberg, R. Sandboge. Journal of Computing and Information Science in Engineering, July 22, 2013, 13(3), 031007.


In every set of assembled products, there are geometrical variations and deviations from nominal dimensions. This can lead to products that are difficult to assemble or products not fulfilling functional or aesthetical requirements. In several industries, variation simulation is used to predict assembly variation in the development phase. This analysis is usually done under room temperature conditions only. However, for some materials, such as plastics, the thermal expansion can be significant in the intended environmental span of the product. In an assembly, this can lead to thermal stresses and parts that will deform. To avoid this problem, locating schemes need to be designed to allow for the right behavior while exposed to varying temperatures.

In this work, the effect of thermal expansion is studied in the context of variation simulation. A virtual tool for this purpose is also presented. Two case studies from the automotive industry are used where the combined effect of thermal expansion and assembly variation is analyzed. It is shown that it may not be sufficient to simply add the result from thermal analysis to assembly variation. Hence, to assure the geometrical and functional quality of assembled products during usage variation simulations need to be combined with thermal expansion simulation.


This work is part of the ProViking project “Variation Simulation for Light Weight Assemblies,” financed by Swedish Foundation for Strategic Research carried out as a part of the Wingquist Laboratory VINN Excellence Centre research program and Chalmers Production Area of Advance. The support is greatly acknowledged.

Authors and Affiliations

  • S. Lorin, Fraunhofer-Chalmers Centre
  • L. Lindkvist, Department of Product and Production Development, Chalmers University of Technology
  • R. Söderberg, Department of Product and Production Development, Chalmers University of Technology
  • R. Sandboge, Fraunhofer-Chalmers Centre

Photo credits: Nic McPhee