拉索加强式温室单层球面网壳稳定性分析

发布时间：2019-03-14 10:37

【摘要】：双向网格型单层球面网壳透光好、耗材小、作为温室结构设计具有广泛的应用前景。但是结构面内刚度和面外刚度较低,过度增大跨度易发生大变形导致结构失稳。为了提高结构的稳定性能,针对30、40、50 m跨度的单层球面网壳提出了在双向网格对角处即面内布置拉索及和面外不相邻节点处布置斜拉索的方案,开发了刚性网壳和柔性拉索组成的拉索加强式温室空间结构体系。利用有限元程序ANSYS以及自编的前后处理程序,针对不同跨度温室球面网壳进行了弹性、弹塑性全过程分析,考察了拉索布置形式、拉索预应力、初始几何缺陷、荷载不对称分布等因素对温室网壳稳定性的影响规律,并结合结构的屈曲模态、塑性发展分布等特征响应,进一步揭示了结构的失稳机理。在此基础上,分析了材料非线性对温室网壳稳定性的影响规律,通过对网壳结构的弹性、弹塑性临界荷载的统计,重新核定了此类温室结构体系的"塑性折减系数"。结果表明:拉索充分发挥了材料的抗拉性能,布置拉索后使原结构极限荷载提高了29%~92%,对拉索施加30 k N预应力后极限荷载最大可提高43%,论证了该结构形式的合理性;塑性折减系数在0.7~1.0之间,说明材料非线性对此类温室结构稳定性的影响不大,以上研究成果对该结构体系的工程实践提供了技术参考。
[Abstract]:Bi-directional gridded single-layer spherical reticulated shell has a wide application prospect as a greenhouse structure design because of its good light transmittance and small material consumption. However, the in-plane stiffness and the out-of-plane stiffness of the structure are relatively low. In order to improve the stability of the structure, aiming at the single-layer spherical reticulated shells with a span of 30,40,50 m, a scheme of laying cables in the right plane at the diagonal of the two-way grid and cable-stayed cables at the non-adjacent joints on the outside of the two-way grid is proposed. A spatial structure system of cable reinforced greenhouse composed of rigid reticulated shell and flexible cable is developed. Based on the finite element program ANSYS and the pre-and post-processing program, the elastic and elastic-plastic whole process analysis of spherical latticed shell of greenhouse with different span was carried out, and the cable layout, prestressing force and initial geometric defect were investigated. The influence of load asymmetry and other factors on the stability of greenhouse latticed shell, and the structural buckling mode, plastic development distribution and other characteristics of the response, further reveal the instability mechanism of the structure. On this basis, the influence of material nonlinearity on the stability of greenhouse latticed shell is analyzed. The "plastic reduction factor" of this kind of greenhouse structure system is re-approved through the statistics of elastic and elasto-plastic critical load of reticulated shell structure. The results show that the tensile cable makes full use of the tensile properties of the material, and the ultimate load of the original structure is increased by 29% / 92% after the cable is arranged, and the maximum ultimate load of the cable is increased by 43% after applying 30 K N prestress to the cable. The rationality of the structure is demonstrated. The plastic reduction coefficient is between 0.7 and 1.0, which shows that the material nonlinearity has little effect on the structural stability of this kind of greenhouse. The above research results provide technical reference for the engineering practice of the structure system.
【作者单位】：东北农业大学水利与建筑学院;哈尔滨工业大学土木工程学院;
【基金】：黑龙江省博士后基金项目(LBH-Z14095) 中国博士后基金项目(2015M571421) 国家自然科学基金青年科学基金项目(51109037) 东北农业大学“青年才俊”项目(518024)
【分类号】：TU399

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