Measuring piston head impact
Weber-Hydraulik (Hyco Canada ltd) asked Creaform to perform the structural analysis of a piston undergoing an impact at a 2 feet per second velocity. A non-linear transient simulation under an implicit calculation scheme was used in order to assess the strength of the assembly. Non-linear boundary conditions were used to represent the impact scenario.
Initial velocity and contact algorithms between the moving part and cylinder as well as tuned structural damping to represent viscosity of surrounding fluid were used to represent impact dynamics.
All material models were chosen to accurately predict this non-linear event and assess any possible mechanical failure due to the impact event. High quality mesh, mostly hexahedral elements, was used to predict stresses with precision. Welded joints and bolted connection were also explicitly modelled in order to capture any possible failure.
The integrity of the structure, based on computed margins of safety on structural components, welds and joints, was demonstrated for a two-feet-per-second impact scenario.
The project required knowledge and techniques within the field of dynamic transient analyses in order to choose proper parameters, such as contact algorithms and damping values.
- Finite element modeling
- Non-linear implicit transient analysis for impact scenarios
- Margins of safety calculations for metallic components and interface joints (fasteners)
Tools and Methods Used
Based on the client’s needs, Creaform used the following tools and methods:
- NEi Nastran
- Non-linear transient analysis