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针对船舶艉轴承的减振降噪进行橡胶材料硬度对艉轴系振动影响的试验研究。通过Pulse振动分析平台对艉轴承的振动情况进行数据采集和分析,应用振动频谱分析法得出对于常工作在低速重载工况下的水润滑橡胶轴承其内表面宜趋近的邵氏硬度为80时,对于中高速则可稍微提高一些。 相似文献
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船用艉轴承支撑着悬伸于船外的螺旋桨轴,由于螺旋桨的重力作用,其轴颈中心线不再平行于轴承孔中心线,而是在竖直平面内发生倾斜。轴颈倾斜使轴承膜厚及压力沿轴向不再均匀分布,显著降低轴承承载能力,使之处于混合润滑状态,且易导致碰磨、严重磨损甚至轴瓦烧焦等问题,严重危害轴系服役安全。为提高轴颈倾斜下水润滑艉轴承的性能,改善压力分布,提出了一种采用复合衬层的轴承设计方法,以高分子材料作为承载表面,在高分子承载层与金属外壳之间加入橡胶层,橡胶层为等厚或非等厚结构。在此基础上建立了复合衬层水润滑轴承的混合润滑模型,分析了单一衬层结构、等厚复合衬层结构及非等厚复合衬层结构下的轴承性能。结果表明,对于处于混合润滑状态的水润滑轴承,复合衬层改善了压力分布、降低了摩擦因数和混合润滑状态过渡到流体动力润滑状态时的转速,而非等厚复合衬层对润滑性能具有更显著的改善作用。总结得到非等厚复合衬层轴承最优橡胶层厚的拟合公式,并给出了公式的适用范围,公式形式简洁,便于应用于轴承设计计算。相关工作为船用轴承优化设计和承载能力提升提供了新思路。 相似文献
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研究推进轴系橡胶艉轴承刚度等效方法,给出重力作用下的轴系艉轴承的等效支承位置及刚度。建立转轴-轴承非线性接触有限元模型,获得轴承表面压力和位移分布,然后采用单点、多点支承模型进行刚度等效。结果表明,单点支承等效可以较为准确地描述转轴位移,但转角不够准确;5点支承等效较单点支承等效具有更高的精度,可以较为准确地描述轴系变形,而且动刚度等效也能较准确地描述频响特性(微幅振动条件下),尤其对于低频区域(小于60 Hz),与转轴-轴承接触模型的计算结果几乎一致。 相似文献
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现代机械产品的设计,不再仅仅局限于对于产品结构性能的满足上,还要满足节约材料的要求,从而控制零件制造成本。对于现代设计,形状优化时在设计过程中必须考虑的问题,各种方法的使用,使形状优化下的机械设计更加具有合理性和结构稳定性,特别是利用计算机的形状优化,更是在机械设计方面提高了设计的科学性。 相似文献
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润滑轴承的有限元分析及其多重网格算法 总被引:3,自引:0,他引:3
有限元分析方法是一种非常有效的求解一类数学问题的方法,它广泛地应用于工程计算。有限元方法计算的精度、速度、所需的内存容量与区域单元划分的疏密有决定性的关系。探讨了在大规模单元划分情况下使有限元分析易于实施的多重网格法,以实例说明了该算法具有更强的适应能力。 相似文献
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目的研究矿泉水瓶体凹槽结构形状的优化设计。方法在有限元显式分析软件LS-DYNA中,通过不同厚度分布的实常数,建立厚度可连续变化的瓶体壳模型。针对影响瓶体垂直载压能力的凹槽形状参数,包括凹槽内高度、深度以及拔模角度,设计正交试验。在正交试验的基础上,利用单因素试验优化外部拐角处的倒角半径。结果通过正交试验的极差分析,确定凹槽内高度2 mm,槽深度1 mm,拔模角度2°为最优方案。在单因素试验的基础上,综合美学和生产方面的考虑,确定倒角半径1 mm为最优方案。结论以矿泉水瓶体垂直载压能力所受影响最小为目标,得到了凹槽形状参数的最优组合方案,并为其他参数的优化提供了一种方法。 相似文献
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橡胶艉轴承的试验模态分析 总被引:1,自引:0,他引:1
橡胶艉轴承由于其减振降噪的优良特性,在舰船中的应用越来越广泛。为分析轴承的动态特性,应用锤击法,在LMS系统平台上对橡胶艉轴承整体进行试验模态分析,并应用模态置信判据(MAC值)对试验模态分析结果的正确性进行验证,结果表明基于线性理论的模态分析方法对橡胶轴承进行分析,其试验模态分析得出的固有频率与有限元模态分析得出的固有频率分布范围基本一致,但由于橡胶的非线性造成橡胶轴承的振型与ANSYS计算结果有一定差异,而金属衬套的频率和振型则趋于一致。 相似文献
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薄膜结构中索滑动对结构性能的影响 总被引:3,自引:0,他引:3
薄膜结构的设计经历形状确定分析、荷载性能分析和剪裁分析三个阶段。用有限元单元进行薄膜结构设计时,往往将薄离散为空间薄膜单元,而将索离散为空间索(杆)单元,两者之间共享节点。即假定索与膜之间没有相对滑移。另一方面,薄膜结构为柔性结构,在荷载作用下结构将经历大位移变形。索与膜之间产生相对滑动的可能性较大。本文尝试用有限元来分析薄膜结构中索与膜之间相对滑动对结构性能的影响。包括对外形、受力性能和结构自振特性的影响。所有算例用有限元程序ABAQUS完成。 相似文献
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Sensitivity analysis and shape optimization for preform design in thermo‐mechanical coupled analysis
Z. Y. Gao R. V. Grandhi 《International journal for numerical methods in engineering》1999,45(10):1349-1373
In complex forging processes, it is essential to find the optimal deformation path and the optimal preform shape that will lead to the desired final shape and service properties. A sensitivity analysis and optimization for preform billet shape in thermo‐mechanical coupled simulation is developed in this work. Non‐linear sensitivity analysis of temperatures, flow‐stresses, strains and strain‐rates are presented with respect to design variables. Both analytical and finite‐difference gradients are employed to validate the effectiveness of sensitivity analysis developed in this work. Numerous iterations of coupled thermo‐mechanical analysis are performed to determine an optimum preform shape based on a given criterion of minimizing the objective function on effective strain variance within the final forging. The design constraints are imposed on die underfill, material scrap, folding defects and temperatures. In addition, a method for material data processing is given in order to determine the flow stress and its derivatives. The shape optimization scheme is demonstrated with the preform designs of an axisymmetric disk and a plane strain problem. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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Liu Hong‐Min Zheng Zhen‐Zhong Peng Yan 《International journal for numerical methods in engineering》2001,50(5):1059-1076
This paper puts forward a new method—the streamline strip element method (SSEM) for simulating the three‐dimensional stresses and deformations of strip rolling process. The rolling deformation zone is divided into a number of streamline strip elements along metal flow traces, and the streamline strip elements are mapped onto the corresponding rectangle strip elements for computation. The longitudinal distribution model of the metal lateral displacement is constructed to be a quartic plus cubic curve. The three‐dimensional deformations and stresses of the deformation zone are formulated. For the cold strip rolling on a 300 mm wide four‐high mill, the computed results of the transverse distributions of the rolling pressure and the front and back tension stresses are close to the experimental ones. For the cold strip rolling on a 1850 mm wide six‐high CVC mill, the computed results of the transverse distributions of the front tension stress are also close to the experimental ones. This proves that the streamline strip element is a reliable engineering–computation method, and of great importance to developing the mathematical model of the shape control of strip rolling. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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The research on aggregation structure of PP materials under different condition and the influence on mechanical properties 总被引:1,自引:0,他引:1
In this article, the study of the aggregation structure of PP material with the IAS4 Image Analysis System is reported. The result indicates that the morphology of spherulite or filling particle in the matrix of crystalline polymer can be quantitatively described by the IAS4 Image Analysis System. Through the measurement of the aggregation structure, the transformation of mechanical properties was explained. With the increase of filling quantity of nucleating agent, the crystallinity (Xc) tends to increase, the spherulite size (Dn) and its distribution (Cd) tends towards decline. The different heat treatment technology influenced only the crystallinity but not the spherulite size or its distribution. The effects of Xc, Dn and Cd on mechanical properties were investigated. It was shown that, with the decrease of Xc, Dn or Cd, the notch impact strength increases. To the PP/talc composite, the aggregation of talc particle has relation with the original size of particle, filling quantity and the surface treatment level. With the decrease of particle size or uniform distribution, the notch impact strength rises up. 相似文献
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织物结构对复合材料力学性能影响的试验研究 总被引:2,自引:1,他引:2
为探讨不同结构形式织物对复合材料力学性能的影响及其损伤破坏机制之间的差异,通过宏观拉压试验,研究了经编及平纹碳纤维织物增强树脂基复合材料的拉伸及压缩力学性能,并利用声发射对试验过程进行实时监测,对破坏后的断口进行显微镜观察分析,分别给出了两种材料的拉伸和压缩破坏机制.研究结果表明:织物结构形式对复合材料的力学性能有较大影响,与经编织物复合材料相比,平纹织物复合材料的拉伸、压缩强度均较低,且其拉伸、压缩破坏试样的断口相对齐平,分层现象不明显;根据声发射监测结果可以判定两种复合材料损伤过程中的损伤类型,与经编织物相比,平纹织物复合材料拉/压过程中的声发射电压信号相对稳定且整体强度较低. 相似文献
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不同孔隙率CFRP层合板静态力学性能研究 总被引:1,自引:2,他引:1
为了研究孔隙率对织物碳纤维/环氧树脂复合材料层合板静态力学性能的影响规律,分别测量了孔隙率为0.33%至1.50%的CFRP层合板的弯曲强度和层间剪切强度,并进行有限元模拟.在适用于复合材料单向板的改进Hashin失效准则基础上,建立了适用于织物纤维增强复合材料静态力学强度的失效准则.通过引入复合材料基本强度参数预测不同孔隙率CFRP层合板的力学性能,结合刚度突然退化模型,采用ABAQUS软件建立了有限元模型.试验结果表明,随着孔隙率的增加,复合材料层合板的弯曲强度和层间剪切强度均呈下降趋势.有限元模型较为准确地预测了不同孔隙率织物碳纤维/环氧树脂复合材料层合板的弯曲强度和层间剪切强度. 相似文献
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Xiao-Yan ZHANG Yu-Fei MA Yong-Gang LI Pin-Pin WANG Yuan-Liang WANG Yan-Feng LUO 《材料科学前沿(英文版)》2012,6(4):326
The goal of this study is to design and synthesize a linear segmented shape memory poly(urethane-urea) (SMPUU) that possesses near-body-temperature shape memory temperature (T tran) and enhanced mechanical properties by incorporating flexible poly(ethylene glycol) 400 (PEG400) to form poly(D,L-lactic acid)-based macrodiols (PDLLA--PEG400--PDLLA) and then rigid piperazine (PPZ) as a chain extender to form the desired SMPUUs (PEG400--PUU--PPZ). PEG400 increased M n while maintaining a lower T g of PDLLA--PEG400--PDLLA, which together with PPZ improved the mechanical properties of PEG400--PUU--PPZ. The obtained optimum SMPUU with enhanced mechanical properties (σ y = 24.28 MPa; ? f = 698%; U f = 181.5 MJ/m3) and a T g of 40.62°C exhibited sound shape memory properties as well, suggesting a promising SMPUU for in vivo biomedical applications. 相似文献