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材料的阻尼是衡量材料本身耗能性能的主要指标。在超高韧性水泥基复合材料(UHT-ECC)中掺加一定量的聚合物能够提高UHT-ECC的阻尼。采用自由振动法测试得到了增强阻尼ECC悬臂梁在不同初始顶点位移下的自由衰减曲线,应用信号处理技术得到了构件阻尼比随振幅和聚合物掺量变化的规律。研究了聚灰比、单一乳液及乳液共混对增强UHT-ECC力学性能和悬臂梁阻尼性能的影响。在此基础上,提出了增强阻尼UHT-ECC悬臂梁构件阻尼比的计算理论与方法。试验结果表明:当聚合物采用乳液共混及单一乳液时,最优聚灰比宜分别控制在6%~8%及4%~6%之间,UHT-ECC能够在强度降低不大的情况下,较高地提高其阻尼性能。
Material damping is a measure of the material’s own energy performance of the main indicators. Damping of UHT-ECC can be improved by adding a certain amount of polymer to ultra-high toughness cement-based composites (UHT-ECC). The free attenuation curve of reinforced damping ECC cantilever beam with different initial apex displacements was obtained by the free vibration method. The law of the damping ratio of the member varying with the amplitude and polymer content was obtained by using the signal processing technique. The effects of poly-ash ratio, single emulsion and emulsion blends on the mechanical properties of UHT-ECC and damping capacity of cantilever beams were studied. On this basis, the calculation theory and method for damping damping ratio of UHT-ECC cantilever beams are proposed. The results show that when the polymer is blended with emulsion and single emulsion, the optimal ratio of poly-ash is controlled between 6% ~ 8% and 4% ~ 6%, respectively. UHT-ECC can reduce the strength slightly Under, to improve its damping performance.