木结构螺栓连接承载性能研究

发布时间：2018-06-03 21:09

本文选题：螺栓连接 + 销槽承压　；参考：《哈尔滨工业大学》2014年硕士论文

【摘要】：我国螺栓连接计算方法是假定被连接木构件的木材材质相同,销槽承压采用理想弹塑性本构模型。而美、欧等国家销槽承压采用刚塑性本构模型,考虑被连接构件木材的材质可以不同,并取多种失效模式中对应的最低承载力作为螺栓连接承载力设计值。显然,国外的计算方法更适应现代木结构的需要,而我国的计算方法销槽承压采用理想弹塑性本构模型更加符合实际工况,本文通过大量算例对同种木材采用理想弹塑性模型计算得到的单剪连接螺栓连接理论承载力与通过刚塑性模型计算得到的理论承载力结果进行了对比,承载力计算结果差距在17%以内。说明我国原有的螺栓连接计算假定和推导方法是可行的。本文利用销槽承压理想弹塑性本构模型进行了不同材质木材六种破坏模式的螺栓连接承载力理论计算公式的推导,得到了不同材质木材螺栓连接弹塑性理论承载力计算公式。并通过大量算例对比了刚塑性模型单剪螺栓连接理论和弹塑性模型理论的计算结果,较薄、较厚构件销槽承压和形成两个塑性铰的破坏模式理论承载力计算公式相同,形成一个塑性铰破坏模式承载力差距不大,钢销形成刚体转动破坏模式计算结果相差较大。此外,我国木结构设计规范中取木材的顺纹抗压强度计算螺栓连接的承载力,作为现代木产品,同一树种不同强度等级的木材,由于缺陷的影响,其顺纹抗压强度可以有很大不同,但木材缺陷对其销槽承压强度的影响并不显著,同树种不同强度等级的木材,其销槽承压强度并无很大差别。所以应利用销槽承压强度确定螺栓连接的承载力。针对上述问题,本文进行了12mm、14mm、16mm、18mm钢销直径的樟子松和东北落叶松顺纹、横纹销槽承压试验,共389个试件,并且分别测定了其质量和含水率,得到这两种木材不同钢销直径的顺纹、横纹销槽承压强度和木材气干密度、含水率等,为螺栓连接承载力计算提供了重要参数,并且通过与美国、欧洲销槽承压强度计算结果对比,分析了销槽承压强度和木材材质、螺栓直径的关系。进行了樟子松、东北落叶松顺纹双剪螺栓连接试验,螺栓直径分别为12mm、16mm、18mm,共4种破坏模式,48种连接形式,共144个试件,并利用销槽承压强度试验结论,对比分析了螺栓连接试验结果与弹塑性理论计算结果,发现试验与理论结果符合较好,差距一般都在15%以内,只有一个试验与理论结果相差大于20%。此外,进行了11个12mm螺栓直径樟子松同种木材有垫片的螺栓连接对比试验,发现当螺栓产生弯曲时,螺栓产生的“绳索效应”对承载力有一定提高,其中产生塑性铰的破坏模式中“绳索效应”对螺栓连接承载力提高达到30%以上。有限元分析弹性阶段采用多孔弹性模型,塑性阶段采用Drucker-Prager本构模型,引入试验得到的参数对试验模型进行有限元分析,有限元模拟破坏模式、承载能力和试验结果符合较好。且数值模拟、试验结果、理论推导得到的螺栓连接承载力符合较好。最后,通过理论分析得到了木结构螺栓连接承载力设计公式,并确定了设计公式中销槽承压强度、螺栓强度的取值。
[Abstract]:The calculation method of bolt connection in China assumes that the wood material of the connected wood is the same material, and the ideal elastoplastic constitutive model of the pin groove is adopted. While the rigid plastic constitutive model is adopted in the pin trough of the United States, Europe and other countries, the wood material of the connected component can be different, and the corresponding minimum bearing capacity of various failure modes is taken as the bolt connection. It is obvious that the calculation method abroad is more adaptable to the needs of modern wood structure, but in our country, the ideal elastoplastic constitutive model is more in line with the actual working conditions. In this paper, the theoretical bearing capacity of the single shear connection bolt connection obtained by an ideal elastoplastic model for the same kind of wood is calculated by a large number of examples. Compared with the theoretical bearing capacity results obtained by the rigid plastic model, the difference between the calculation results of the bearing capacity is less than 17%. It shows that the original calculation hypothesis and the derivation method of the bolt connection in our country are feasible. In this paper, the bolt connection of the six failure modes of wood with different material is carried out by the ideal elastoplastic constitutive model of the pin trough bearing. Based on the derivation of the theoretical calculation formula of the bearing capacity, the elastic and plastic theoretical bearing capacity of wood bolt connection of different materials is obtained. Through a large number of examples, the calculation results of the single shear bolt connection theory and the elastoplastic model theory of the rigid plastic model are compared, and the failure modes of the two plastic hinges and the pressure of the thicker component pin and the formation of the plastic hinge are compared. On the same calculation formula of bearing capacity, the bearing capacity of the failure mode of a plastic hinge is not large, and the calculation result of the rigid body rotation failure mode of the steel pin is quite different. In addition, the bearing capacity of the bolt connection is calculated by the CIS compression strength of wood structure in our country. As a modern wood product, the strength grade of the same tree is different. Because of the effect of defects, the compressive strength of the wood can be greatly different, but the effect of wood defects on the pressure strength of the pin groove is not significant. There is no significant difference in the compressive strength of the grooves with the wood of different strength grades. Therefore, the bearing capacity of the bolt connection should be determined by the pressure of the pin groove. 12mm, 14mm, 16mm, 18mm steel pin diameter of Pinus sylvestris and Larix gmelinii, 389 specimens were tested, and their quality and moisture content were measured respectively. The CIS grain of the two kinds of steel pin diameter, the pressure strength of the transverse pin grooves and the dry density of wood gas, water content, etc. were used as the bolt connection bearing meter. An important parameter is provided, and the relationship between the pressure strength of the pin and the wood material and the diameter of the bolt is analyzed by comparison with the calculation results of the pressure strength of the American and European grooves. The bolt connection test of Pinus sylvestris and northeastern Larix Larix is carried out, the diameter of the bolt is 12mm, 16mm, 18mm, and 48 kinds of connection forms, a total of 14. The results of bolt connection test and elastoplastic theory are compared and analyzed with 4 specimens. The results show that the results are in good agreement with the theoretical results, and the gap is generally within 15%. Only one test and theoretical results are more than 20%., and 11 12mm bolt diameter of Pinus var. The bolted connection test of the gasket shows that when the bolt is bending, the "rope effect" produced by the bolt has a certain increase in the bearing capacity of the bolt. In the failure mode of the plastic hinge, the "rope effect" increases the bearing capacity of the bolt to more than 30%. The elastic model of the finite element analysis is adopted in the elastic stage and the plastic stage is adopted. The Drucker-Prager constitutive model is introduced by the finite element analysis of the experimental model by the parameters obtained by the test, the finite element simulation of the failure mode, the bearing capacity and the test results are in good agreement. And the numerical simulation, the experimental results, the theoretical deduction of the bolt connection bearing capacity is good. Finally, the wood structure bolt connection is obtained by theoretical analysis. The design formula of the bearing capacity is determined, and the value of the strength of the groove and the strength of the bolt are determined.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU366.2

【参考文献】