Understanding of scratch behavior of an automotive coating system: Experiments and finite element analysis

Abstract

As one of the most important components of a vehicle, the automotive coating system is typically a multi-layer polymeric structure with complex scratch damage patterns. This work is the first one to systematically investigate the scratch performance of an automotive coating system via experimental and numerical approaches. To achieve this end, uniaxial tensile tests are firstly carried out to acquire the basic mechanical properties of paint films at different strain rates. Then, a series of scratch tests are conducted in accordance with ASTM D7027/ISO 19252 standards, and the damage features are identified. In addition, the effects of scratch speed, loading rate, and stylus type are experimentally investigated. Afterwards, a finite element approach for scratch simulations is developed, which includes a rate-dependent constitutive model calibrated using the uniaxial tensile tests, a tied interface algorithm for efficient connection between coating and substrate, and an interior contact method to avoid excessive element distortions. Eventually, with the aid of the presented numerical approach, the damage patterns observed in scratch tests are numerically explained, and the scratch damage process is reasonably surmised. The presented approaches and findings can contribute to the development of anti-scratch automotive coating structures.