Dampers provide safety by controlling unwanted motion that is caused due to the conversion of mechanical work into another form of energy (e.g., heat). State-of-the-art materials are elastomers and include thermoplastic elastomers. For the polymer-appropriate replacement of multi-component shock absorbers comprising mounts, rods, hydraulic fluids, pneumatic devices, or electro-magnetic devices, among others, in-depth insights into the mechanical characteristics of damper materials are required. The ultimate objective is to reduce complexity by utilizing inherent material damping rather than structural (multi-component) damping properties. The objective of this work was to compare the damping behavior of different elastomeric materials including thermoplastic poly(urethane) (TPU) and silicone rubber blends (mixtures of different poly(dimethylsiloxane) (PDMS)). Therefore, the materials were hyper- and viscoelastic characterized, a finite element calculation of a ball drop test was performed, and for validation, the rebound resilience was measured experimentally. The results revealed that the material parameter determination methodology is reliable, and the data that were applied for simulation led to realistic predictions. Interestingly, the rebound resilience of the mixture of soft and hard PDMS (50:50) wt% was the highest, and the lowest values were measured for TPU.
Low pressure fluid transport (1) applications often require low and precise volumetric flow rates (2) including low leakage to reduce additional costly and complex sensors. A peristaltic pump design (3) was realized, with the fluid’s flexible transport channel formed by a solid cavity and a wobbling plate comprising a rigid and a soft layer (4). In operation, the wobbling plate is driven externally by an electric motor, hence, the soft layer is contracted and unloaded (5) during pump-cycles transporting fluid from low to high pressure sides. A thorough characterization of the pump system is required to design and dimension the components of the peristaltic pump. To capture all these parameters and their dependencies on various operation-states, often complex and long-lasting dynamic 3D FE-simulations are required. We present, here, a holistic design methodology (6) including analytical as well as numerical calculations, and experimental validations for a peristaltic pump with certain specifications of flow-rate range, maximum pressures, and temperatures. An experimental material selection process is established and material data of candidate materials (7) (liquid silicone rubber, acrylonitrile rubber, thermoplastic-elastomer) are directly applied to predict the required drive torque. For the prediction, a semi-physical, analytical model was derived and validated by characterizing the pump prototype.
Transportation infrastructure relies heavily on asphalt pavement, but conventional bitumen-based mixtures present several drawbacks. This study assesses the potential of poly(methyl methacrylate) resins and thixotropic fillers as substitutes for bitumen to improve pavement performance. The research concentrates on enhancing current formulations that incorporate a thermosetting polymer and mineral (stiffening) fillers, with the objective of increasing durability, extending the product life cycle, and optimizing raw material usage. Utilizing dynamic thermomechanical analyses, the viscoelastic characteristics of resins are examined, with a focus on their mechanical properties’ dependence on load frequency and temperature. The investigation also evaluates the impact of different fillers, including silica sand, silica dust, and basalt sand, on viscoelastic behavior and load-bearing capacity, offering valuable insights into the relationships between material structure and properties. The findings reveal that stiffness is predominantly affected by the quantity of silica dust, whereas the force plateau depends on the amount of sand. This study contributes crucial information for the development of more sustainable and robust pavement materials for future applications.
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