THE FREQUENCY-DEPENDENT STUDY ON VISCOSITY COEFFICIENT AND LOSS TANGENT OF VISCOELASTIC MATERIALS
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摘要: 针对黏弹性材料KV阻尼模型的黏滞系数与复阻尼模型的损耗因子间的关系,由单自由度体系的结构动力学分析,并基于结构振动响应的一致性,推导建立了黏滞系数与损耗因子在结构线性稳态简谐振动和自由振动时的一般关系式;并利用该关系式,试验研究了纤维混凝土材料黏滞系数和损耗因子的频率相关性.结果表明,黏滞系数与损耗因子间的关系在稳态简谐振动和自由振动时的表达形式相同,只是频率取值不同;纤维混凝土的损耗因子和黏滞系数都随频率增加而降低,且在0.5～1.0Hz频段降幅显著,而后渐趋平缓;相比于素混凝土,纤维混凝土的黏滞系数和损耗因子与激振频率的相关性更强.试验所得纤维混凝土频率相关的黏滞系数、损耗因子及推导所建立的两参数关系式为构建物理意义明确且又便于结构振动反应分析的阻尼系数或阻尼矩阵奠定了基础.Abstract: According to the relationship between viscosity coefficient of viscoelastic damping model and loss tangent of complex damping model,and the consistency of structural vibration response,the general expression of viscosity coefficient and loss tangent of viscoelatic material was deduced by SDOF's dynamic analysis when the system was in steady-state harmonic vibration or free vibration.Furthermore,the experimental investigation was carried out to study the frequency-dependent viscosity coefficient and loss tangent of fiber reinforced concrete material.It has been shown that,for the steady-state harmonic vibration and free vibration,the expressions of viscosity coefficient and loss tangent were identical except the given vales of frequency.The loss tangent and viscoelastic coefficient of fiber reinforced concrete was decreased with increasing frequency,and decreased shapely among 0.5 to 1.0Hz,then decreased smoothly.Compared with the control plain concrete,the influence of frequency on loss tangent and viscoelastic coefficient of fiber reinforced concrete was more significant.The frequency-dependent viscosity coefficient and loss tangent and the deduced two parameters expression,validated by experiments,are significant important for building damping coefficient or damping matrix which have explicit physical meaning and is convenient for structural vibration response analysis.
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