共查询到20条相似文献,搜索用时 328 毫秒
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由于近年来换能器材料的发展,主动控制技术已逐渐用于控制物体表面的声反射。本文探讨了用于降低表面声反射的主动消声瓦,该消声瓦包括声传感层和传递层。对于具有不同结构的多层换能器系统进行了模拟。对衰减性能、使用和控制的稳定性等动态性能进行了评估。对三维效应,如辐射阻抗和散射对性能的影响也进行了研究。 相似文献
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使用ABAQUS中内嵌的声 - 固耦合法计算了圆板模型遭受水下冲击波载荷作用的响应,并将计算结果与实验值进行比较,数值结果与实验值吻合良好,验证了声 - 固耦合法模拟水下爆炸的准确性;对铝合金圆板和钢板进行了比较,考虑了结构质量,材料应变率和屈服极限,药量和爆距的影响;建立了1艘小型铝合金艇的有限元模型,使用同样的方法分析了铝合金艇遭受水下冲击波载荷的动力响应特性.得出了铝合金艇典型位置的加速度、速度和位移等响应量的时间历程曲线.此外,还得出了塑性变形区域和塑性变形曲线.这些计算结果对铝合金舰艇的抗冲击特性具有一定参考价值. 相似文献
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本文系统研究了一种薄板声子晶体的低频隔声特性,薄板声子晶体由单层均质薄板和正方周期的支撑框架构成。首先,通过有限元方法研究薄板声子晶体的隔声特性和声振模态;进一步分析原包周期、薄板厚度等参数对隔声特性的影响规律;研究结果表明薄板声子晶体在低频段(100~400 Hz)具有很好的隔声特性,尤其在设计的共振频率315 Hz,相对于同质量的单层均质板,隔声量提升了约9 dB。其次,利用3D打印技术制作了试验样件并进行隔声性能测试,试验结果与理论计算结果吻合的很好。该研究为轻质隔声材料设计及低频噪声控制提供了很好的技术支撑。 相似文献
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针对玻璃钢电缆管具有轻质高强、耐腐蚀、寿命长、施工方便、工程造价低、综合效益好的特点,介绍玻璃钢电缆保护管的概况。介绍了玻璃钢电缆保护管的技术规格和安装方法。将玻璃钢电缆保护管和镀锌钢管性能进行对比。实践证明:玻璃钢电缆保护管由于其优良性能,在港区堆场应用中有着广阔的发展前景。 相似文献
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通过采用钢框模板结合水下不离析混凝土以及对玻璃钢夹砂排水管采用抱箍的施工方案,成功解决了在较短工期内完成抛石棱体中出水口施工难度大的问题。 相似文献
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船用厚板高强度钢焊接性及其焊接裂纹的形成和预防 总被引:1,自引:0,他引:1
随着各类大型化、超大型化船舶的诞生,使得厚板高强度钢的使用日益广泛,但随之而来的是此类高强度钢易产生焊接裂纹的问题。文章列举了国内外船用厚板高强度钢焊接的工艺特点,分析了焊接裂纹的起因,并就预防措施进行了初步探讨。对从事船体结构的研究人员有一定的帮助。 相似文献
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《船舶与海洋工程学报》2019,(3)
The hydroelastic response of very large floating structures(VLFS) under the action of ocean waves is analysed considering the small amplitude wave theory. The very large floating structure is modelled as a floating thick elastic plate based on TimoshenkoMindlin plate theory, and the analysis for the hydroelastic response is performed considering different edge boundary conditions.The numerical study is performed to analyse the wave reflection and transmission characteristics of the floating plate under the influence of different support conditions using eigenfunction expansion method along with the orthogonal mode-coupling relation in the case of finite water depth. Further, the analysis is extended for shallow water depth, and the continuity of energy and mass flux is applied along the edges of the plate to obtain the solution for the problem. The hydroelastic behaviour in terms of reflection and transmission coefficients, plate deflection, strain, bending moment and shear force of the floating thick elastic plate with support conditions is analysed and compared for finite and shallow water depth. The study reveals an interesting aspect in the analysis of thick floating elastic plate with support condition due to the presence of the rotary inertia and transverse shear deformation. The present study will be helpful for the design and analysis of the VLFS in the case of finite and shallow water depth. 相似文献
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《Marine Structures》2004,17(1):1-27
This paper presents a combined experimental–numerical procedure for development and calibration of macroscopic crack propagation criteria in large-scale shell structures. A novel experimental set-up is described in which a mode-I crack can be driven 400 mm through a 20(+) mm thick plate under fully plastic and controlled conditions. The test specimen can be deformed either in combined in-plane bending and extension or in pure extension. Experimental results are described for 5 and 10 mm thick aluminium and steel plates. By performing an inverse finite-element analysis of the experimental results where the simulated crack growth is forced to correspond to the experimental observations, empirical criteria for ductile crack propagation emerge very clearly. Using the experiments with edge crack specimens (ECS) in combined in-plane bending and extension, crack propagation criteria are developed for steel and aluminium plates, mainly as curves showing the critical element deformation versus the shell element size. These derived crack propagation criteria are then validated against a separate set of experiments considering centre crack specimens (CCS) which have a different crack-tip constraint. The applicability of the often-used equivalent strain criterion is discussed versus a more rationally based criterion which takes into account the stress tri-axiality. A large-scale grounding experiment is also simulated showing very good agreement with measurements. The performance of the proposed model is in general good and it is believed that the presented results and experimental–numerical calibration procedure can be of use in practical finite-element simulations of collision and grounding events with the use of shell elements. As discussed, the paper provides a clean framework for further development of macroscopic crack propagation criteria in large-scale plate structures. 相似文献