【作者】 薛启超；

【导师】 邹广平；

【作者基本信息】 哈尔滨工程大学 ， 工程力学， 2013， 博士

【摘要】 聚氨酯弹性体钢夹层板结构是近年来出现的一种新型夹层板结构，广泛应用于船舶结构和桥梁结构的建造和修复工程中。聚氨酯弹性体钢夹层板结构具有强度高、制造加工方便、工业化程度高等特点使其具有广泛的应用前景。由于聚合物夹芯的存在，使得夹层板结构还具有优异的抵抗冲击、振动和疲劳的性能以及隔声、隔热性能好的优点。本文针对聚氨酯弹性体钢夹层板的力学性能进行系统的研究，具体研究内容如下：1、研究了聚氨酯弹性体的制备方法，开展了制备实验，研究了聚氨酯弹性体硬度随时间的变化关系。并开展了带肋钢夹层板试件的制备方法研究，给出了浇筑过程中的流速、管道直径和控制压力之间的关系，开展了聚氨酯弹性体的基本力学性能实验，并根据试验结果分别用两参数和三参数固体模型描述其粘弹性本构关系。2、根据经典夹层板理论提出了一种基于挠度分析的夹层板弯曲等效方法，对经典的理论方法在保证足够精度的情况下进行近似的替代，此方法避免了经典夹层板理论建立偏微分方程组进行求解的缺点，便于广大工程技术人员理解和应用。还对内部带有隔板的聚氨酯弹性体钢夹层板结构的等效参数进行了计算，并使用有限元方法对计算得到的等效参数进行了验证。针对聚氨酯弹性体具有的粘弹性力学性能，文中还根据考虑粘弹性夹芯的Kelvin本构模型，对粘弹性夹芯夹层梁结构在静载和循环载荷下的挠度响应进行了计算和分析。3、在经典的带肋梁板组合结构临界屈曲应力分析的基础上，在分析过程中引入了屈曲折减系数，提出了对带肋夹层板结构进行临界屈曲载荷进行分析的理论方法，并对带肋聚氨酯弹性体钢夹层结构使用有限元工具进行特征值屈曲分析，开展了隔板夹层结构的屈曲实验，对实验结果、理论分析结果和有限元结果进行了对比，验证了分析的正确性。分析了SPS结构的皱曲问题。4、对聚氨酯弹性体夹芯板进行了三点弯曲实验，实验发现在弯曲挠度超过一定程度时，卸载后裂纹会在一段时间内继续发生扩展。根据观察不同种类夹芯的DCB实验和SLB实验发现裂纹扩展角度对同一种试件相同。据此推导了根据裂纹扩展角度描述的临界应变能释放率的计算公式。同时还提出了使用层间粘结强度来评价试件临界破坏准则的方法，获得了软夹芯试件和硬夹芯试件的临界破坏的裂纹长度。5，开展的聚氨酯弹性体夹层梁试件的小变形阶段和大变形阶段的疲劳实验，使用第3章中的理论对聚氨酯弹性体夹芯梁疲劳试验中加载频率的影响进行了分析，发现了聚氨酯弹性体夹芯板材料在弯曲疲劳时存在停歇效应，并根据此提出了包含停歇效应的线性疲劳损伤模型，并给出了回复程度的表达式，用来计算停歇时间而导致的疲劳寿命的增加，最后开展了停歇疲劳实验，验证了停歇效应及提出的疲劳损伤模型。更多还原

【Abstract】 Sandwich Plate System (SPS) is composed of two pieces of steel faceplates and one softpolyurethane core. It was a new kind of sandwich plate appeared at recent years and was wildlyused in construction and reparation in shipbuilding and bridges structure for high strength, rapidreparation and better industrialization. The existing of Polyurethane elastomer make SPS hasmany special additional properties, such as weight reduction, resisting impact. dynamic response,enhancement in the random fatigue behavior, significant acoustic performance and heat insulation.A series of studies on mechanical properties on SPS are carried out in this thesis, and somecontents are listed as followings:1. The preparing method and experiments of polyurethane elastomer are studied and timehistory of hardness was also obtained. On this basis, preparing method of SPS with stiffeningribs was elaborated and the relationship among flow velocity, diameter of tube and pilot pressureis discussed. Fundamental mechanical tests are carried out and viscoelastic constitutive relationswere constructed according to the test results.2. A new equivalent bending analysis method of sandwich plate is proposed based onclassical sandwich bending theory, which can be approximately replaced in enough accuracy.This method avoid the disadvantage of establishing differential equations to be solved inclassical bending sandwich theory, and can be easily understood to apply by engineers.Furthermore, equivalent parameters of SPS reinforced by cross wall are calculated and a FEAmethod is also used to obtain equivalent parameters to compare with the theoretical results. Forviscoelasticity of polyurethane core, bending responses of sandwich plate consideringviscoelasticity of Kelvin constitute relation are also analyzed in case of static loading and cyclicloading.3. On the basis of research of traditional stiffened steel plates, through introducing criticalreduction coefficient of critical load, a theoretical analysis method is proposed to calculatecritical loads of SPS with stiffening ribs. At same time, Eigen value analysis by FEM andbuckling tests of stiffening SPS is also carried out to verify the correctness of theoretical analysis.Local buckling of SPS is also discussed here and critical wrinkling load of faceplate iscalculated. 4.3-points bending tests for sandwich beam specimens with polyurethane core are carriedout and a special failure phenomenon was found that the interface crack will propagate afterunload and the process will last a certain time. From DCB and SLB tests, it is found that thepropagating angle of interface crack has same value for same kind core in different DCB andSLB test. According to the observation of test, a new kind of calculation method is deduced toelaborate critical strain energy release rate. At the same time, the analysis method of criticalfailure criteria is also proposed by using of interface bonded strength, and critical crack lengthcan be obtained.5. Fatigue tests for sandwich beam in elastic stage and plastic stage are carried out in lastchapter. The influence of frequency to the fatigue test is analyzed by using of theoretical methodproposed in chapter3, and found that there exist "rest" effect in fatigue test for sandwich beamwith polyurethane core.. a new liner damage model considering "rest" effect is proposed and the"recover" function is also given which can be used to calculate the increase of fatigue life. Lastly,dewell fatigue test is carried out to verify the "recover" phenomena and fatigue damage modelconsiderting dewell effect.更多还原