Improvement Of Dynamic Relaxation Method And Its Application In Form-finding Of Shell Structures

Shell structures are preferred by architectural designers due to their graceful shapes and mechanical rationality.How to keep shell structures in full pressure or tension therefore making full use of materials is always the purpose of researchers.Since modern times,scholars have proposed Finite Element Method,Dynamic Relaxation Method and Force Density Method for this purpose.These methods are able to conduct form-finding efficiently and obtain both elegant and mechanically rational structures under specified conditions.However,methods mentioned above which focus mainly on form-finding results and ignore the process are incapable of providing an intuitive and thorough understanding of connections between form and force of complicated shell structures for designers.Therefore,with regards to this problem this article proposed a new form-finding method by summarizing the properties of GSM and DRM and elaborated on the establishment,properties and application of the new method to visualize the form-finding process and provided a new perspective for understanding the mechanical behaviou r of shell structures with architectural designers and researchers.This article focuses mainly on the propose of the new method and verification of its viability.With regards to the non-intuition and low efficiency of existing methods,this article proposed a new method which combined the advantages of GSM and DRM,namely GSM-DRM,based on original DRM.This article mainly completed the following works,(1)The improved DRM which introduced GSM(GSM-DRM)was proposed.This method disassembles the form-finding process into two parts.Firstly,the normal force diagram of initial form diagram of relating shells in horizontal surface is generated.The force diagram is manipulated to equilibrate the system statically thus distribution of member force components is obtained in horizontal surface.Then form-finding in vertical space is conducted using DRM thereafter the global static status is achieved by virtual vibrating and dissipating the potential energy.(2)Based on established method,form-finding was conducted for regular hexagon grid shells,square grid shells,regular triangular grid shells and regular triangular continuous shells thereafter the properties of the method was analyzed and the feasibility under various topological relationships was compared.(3)The feasibility of the new method was tested in realistic engineering by conducting form-finding of three examples.The properties and novelty of the new method proposed i n this article are: inner forces distribution in form-finding process can be controlled directly by manipulating the horizontal force diagram therefore modul ing the developing tendency of the system;GSM and DRM are integrated to consider both controllability and efficiency of form-finding process;the horizontal projection of form-finding results are grid-homogenized which is beneficial for real construction and panel installation.