Mechanical and acoustic performance prediction model for elastomers in different environmental conditions

Abstract

This study focuses on the constitutive model including temperature and pressure effects to investigate the dynamic, mechanical and acoustic properties of elastomers in frequency domain under different underwater conditions. The developed constitutive relation is based on Harvriliak-Negami (H-N) model by implementing experimental Young's modulus data and by using Williams-Landel-Ferry (WLF) shift function for relaxation time calculation. The H-N model accurately captures the dynamic mechanical modulus for wide range of frequencies for constant temperature and pressure based on measured DMTA (dynamic mechanical thermal analysis) data. Since the WLF shift function is related with the relaxation time for different temperatures and pressures, the proposed model represents a simple and accurate prediction of dynamic modulus for varying external conditions. Relationship between Young's modulus and acoustic properties of the rubber structure can be established by investigating the hydro-wave propagation process. The predictions from the proposed model are verified by comparing with mechanical and acoustic experimental data at different temperatures and pressures. Additionally, the parametric study is conducted to investigate the effect of H-N parameters on mechanical and acoustic properties of elastomer materials. The proposed model can be used to predict the mechanical and acoustic properties in different environmental conditions accurately.

From Local Structure to Overall Performance: An Overview on the Design of an Acoustic Coating

“…Examples are specified in Table A1 of Appendix A. Owing to its complicated structure, preparation of acoustic coating is difficult, which cannot be verified by experiments, thus making it more difficult for practical applications.Few researches focus on other performance requirements for acoustic coatings during design, such as temperature performance [52], inspection [53]. In different seas, depths, and seasons, seawater temperature changes significantly [1].…”

“…In different seas, depths, and seasons, seawater temperature changes significantly [1]. For more realistic underwater conditions, it is suggested to investigate mechanical and acoustic performances (such as complex elastic modulus) of elastomers in different temperatures and pressures [52]. Researches on low-frequency sound absorption of acoustic coatings are few, especially the study of underwater acoustic materials below 1000 Hz.…”

“…Few researches focus on other performance requirements for acoustic coatings during design, such as temperature performance [52], inspection [53]. In different seas, depths, and seasons, seawater temperature changes significantly [1].…”

Two-dimensional finite-difference time-domain formulation for sound propagation in a temperature-dependent elastomer-fluid medium

“…These environmental-independent parameters can be optimized based on DMTA data including storage modulus and loss factor measured at 20 °C by using MATLAB optimization toolbox (shown in Appendix A). 37 Furthermore, a broader 2-D simulation are also presented by using the proposed FDTD scheme for the water-filled acoustic duct terminated with two kinds of H-N type media. The sound field at different temperature can be observed which is consistent with the actual water-filled standing wave duct applied in hydroacoustic measurements for H-N media.…”