Use Cases

Creep is a time dependent deformation process that happens to materials under a certain stress level. However, with proper design and material choices, thermoplastics can be a suitable material for parts with a creep load. Predictability is key when designing load-bearing components. It reduces development time, enables first-time right design and ensures part performance in service. In this Use Case we evaluated an example of creep of a compression limiter. Focusing on the modelling of creep as function of time of injection molded short-glass-fiber-reinforced plastics (SFRP).

Fatigue is concerned with alternating or cyclic loads, even when the load levels are well below the strength of the applied material. Depending on the component, over time such a load will lead to part failure. Based on conducting extensive experiments, we developed a robust framework considering all essential aspects for fatigue. This Use Case focuses on results of our fatigue/lifetime modelling framework for injection molded glass-fiber reinforced plastics, using the example of the load bracket demonstrator.

Envalior offers many thermoplastics, ranging from high volume polymers to performance and specialty materials. These materials have widely varying properties in the fields of mechanics, chemical resistance, flame retardance and more. They are suitable for production processes such as injection molding, blow molding and extrusion. Besides these materials that are sold as granules, Envalior also offers the base materials for Advanced Thermoplastic Composites (ATC): uni-directional tape and woven fabrics consisting of continuous glass or carbon fibers embedded in a thermoplastic matrix material. These tapes or fabrics can be wound or thermoformed, resulting in parts that have good mechanical properties.

Predictability is key when designing load-bearing components. Predictability reduces development time, enables first-time-right design and ensures part performance in service. In this use case we focus on the prediction of the most important failure modes of plastic gears—static overload, root stress fatigue and wear. Stanyl® is a PA46 based polymer which, due to its chemical composition, is intrinsically very suitable for high load (strength and tribological) and high temperature gear applications. We have developed insights based on in-house dedicated test setups in combination with fundamental polymer mechanics and finite element simulations. These insights enable us to apply our expertise.

For accurate prediction of part strength and absorbed energy, Envalior has created Digimat material cards from high-strain-rate tensile experiments. Digimat material cards model anisotropic viscoelastic/viscoplastic material behavior. In addition, a failure indicator is included in the material card, which allows the user to identify critical locations quickly and easily by post-processing of the finite element analysis (FEA) results.

Based on stress-strain curves measured on tensile bars, we have developed a robust framework to define elasto-plastic material cards that capture the effects of fiber-orientation anisotropy. In this Use Case we are applying these material cards to predict the performance of two in-house demo applications: a load bracket made from Akulon® S223-HG6 (PA66-GF30) and an Electronic Power Steering (EPS) housing made from Xytron™ G4010T (PPS-GF40). The modeling results are within 5% accuracy while the prediction for the modulus is spot-on. This demonstrates the excellent quality of the material cards we have defined.