纸质双层地下空间结构模型设计优化分析

Optimization and design analysis of papery double-layer underground space structure mode

以第七届城市地下空间工程大学生模型设计竞赛为背景,以纸质双层地下空间结构模型为分析实例,从模型概念设计、选型制作、理论计算、数值分析等方面,对模型结构进行了优化分析,完成了加载实验。该模型结构满足题目要求,在承受满载100 kg时,模型结构沉降量仅为2.80 mm。参赛实践表明,大学生模型设计竞赛可以像实际工程结构设计一样,通过概念设计、力学分析、数值计算优化等找到合理的结构设计方案,加上精良的制作工艺和反复练习,能够培养学生的创新能力、动手能力以及团结合作精神。

[Objective]The structural design competition can foster students’practical innovation ability.Moreover,it can play a key role in advancing the training of majors in civil engineering,the development of disciplines,and the transformation of education.Taking the 7th National Structure Design Competition for Undergraduates of Urban Underground Space Engineering as the background,this paper takes the papery double-layer underground structure of the Anhui University of Science and Technology as an example.The model analysis,production,and competition are presented in detail.[Methods]The model structure is optimized and examined regarding the selection manufacture,conceptual design,theoretical calculation,numerical simulation analysis,and model test.First,the mechanical properties and manufacturing methods of papery rods are discussed to determine the best rod specifications as the main element of the model.Second,the preliminary design of the model is established through the conceptual design.Third,the mechanical analysis of different structures,including cross-section,arch frame of four schemes,and beam–column arrangement of four schemes,is performed.The force diagrams of the structure with diverse schemes are obtained.The model is strengthened and simplified according to the force joined with the difficulty of the model production.A structure model with reasonable mechanical behavior and simple production is obtained.Fourth,ABAQUS numerical simulation software is used to perform a numerical simulation analysis on the model under the four conditions of competition:without loading and with loading of 40,70,and 100 kg.The stress and displacement distributions of the model are obtained.Finally,the model test method is used for many attempts.The main points of the model production are summarized.[Results](1)The theoretical calculation results show that the model arch is subjected to a more substantial bending moment,belonging to structural weakness;the straight wall is subjected to a more remarkable axial force,bending moment,and shear force,whereas the foundation and middle plate are subjected to minor force.(2)Similar to the theoretical calculation,the results of numerical simulation reveal that the stress of the arch top,the connection between the arch and straight wall,and the connection between the foundation and the straight wall are more extensive,whereas the stress of the foundation,the middle plate,and the arch connection rod are minor.The maximum stresses of the model without loading and with loading of 40,70,and 100 kg are 4.984×10-2,6.714×10-2,8.014×10-2,and 9.315×10-2 MPa,respectively.(3)In the final competition,the model’s weight is 357.0 g,which meets the structural form requirements of the competition.In the loading test,the settlement of the model is 2.80 mm under loading of 100 kg.According to the scoring calculation rules,87.501 points are obtained,which qualifies for the outstanding prize of this competition.[Conclusions]Similar to the actual engineering structure,the model design competition for undergraduates can achieve satisfactory competition results through reasonable structure design with conceptual design,mechanical analysis,numerical calculation optimization,and excellent production technology and practice.Moreover,it can cultivate students’innovation,practical ability,solidarity,and collaboration spirit.The practical experience of this paper can serve as a reference for the teachers and students who will participate in similar competitions in the future,and experimental teaching can be incorporated into professional courses.