| Popis: |
Soft polymers are widely used as interlayers and adhesives in multi-layered systems for defense applications. This research focuses on the large deformation response of several polyacrylate adhesives with varying microstructures. Understanding the mechanical response of these materials under numerous dynamic loading conditions is instrumental in deriving high fidelity constitutive models and optimizing performance when integrated into a multi-layered structure. In recent years, there has been an emphasis on rate dependence research of soft materials, such as thermoplastic polyurethanes/polyureas (moduli order of 3–5 MPa), at quasi-static and very high rates (SHPB), but not intermediate. The goal is to characterize ultra-soft polyacrylates (moduli on the order of 100–600 kPa) through a wide range of strain rates (0.001–1 /s) using different methods and modes of loading. Methods utilized are Instron (servohydraulic and ElectroPULS) tensile and compression testing, and intermediate instrumented impact on multi-laminates. Characteristics of the large, non-linear deformation testing response include: rate dependence, hysteresis, cyclic effects and strain softening. The microstructure and mechanical behavior of the polyacrylate adhesives is related to the capability to modulate impact loads for loading times of approximately 2 milliseconds. |
