Compliant assembly variation modeling for thin-walled structures considering clamping constraints and geometric deviations based on isogeometric analysis

Geometric deviations and assembly deformations are inevitable in compliant assembly processes and have a significant impact on assembly quality. This paper proposes a variation propagation model based on isogeometric analysis (IGA), which unifies geometric deviations and compliant deformations in one framework by embedding exact geometry into assembly analysis. First, geometric deviations are modeled via offsets along control points using non-uniform rational basis spline (NURBS). Then, the elastic force induced by geometric deviation is calculated using Kirchhoff–Love shell elements. Further, clamping constraints, such as fixture positioning deviation and connection matching deviation, are transformed into displacement boundary conditions using the Lagrange multiplier method. Finally, several examples including the practical project cases are provided to demonstrate the accuracy and efficiency of the developed method in obtaining assembly deviation distributions.