# Geometric Nonlinear Analysis of the Catenary Cable Element Based on UPFs of ANSYS
## 5 Conclusions  
With the emergence and development of more advanced nonlinear mechanics theories, researchers have realized combining theory and experiment through computer programming. Still, due to the shortcomings of programming, it cannot be applied to large and complex structures, while ANSYS, as a large general-purpose software, can solve this problem well. This research mainly combines the nonlinear mechanic's theories with the UPFs technology of ANSYS, integrates the advantages of both, and applies the more advanced nonlinear mechanics theories in ANSYS for computational analysis.  
1. For the nonlinear analysis of cable structures, higher computational accuracy and efficiency are always the goals to be pursued, and when the pretension of the cable structure is high and involves network topology, the accurate initialization solution is essential for the convergence of the nonlinear structure, and this paper adopts the dichotomous method to iterate the initial configuration of the cable unit with pretension to accelerate the convergence and thus improve the computational efficiency.
2. Through the comparison and verification between the example and the engineering model, it can be seen that, according to the characteristics of large span cable-stayed bridges or arch bridges with cable-stayed suspension construction, the initial geometric configuration of the cable is first solved iteratively by the dichotomous method under the known initial tension of the cable, and then the equilibrium equation of the cable element is solved iteratively according to the nonlinear geometric algorithm of the two-node catenary cable element, so the catenary cable element user101 developed in this paper can be directly applied to the ANSYS model for analysis and calculation;
3. A new type of element, user101, developed by using the nonlinear finite element algorithm of the catenary cable element combined with the ANSYS secondary development platform (UPFs), has a certain improvement in nonlinear calculation accuracy and efficiency compared to the existing commercial program ANSYS developed truss  
Figure 13: Maximum tensile stresses of the main arch ring: (**a**) Comparison of maximum tensile stresses in the top slab for different elements and experimental values; (**b**) Comparison of maximum tensile stresses in the bottom slab.  
element, in order to save calculation time without reducing accuracy in the finite element calculation.
* 4. More advanced algorithms can be combined with commercial procedures in subsequent work to develop more novel elements and also provide a new way of thinking for researchers to improve the usefulness of nonlinear theory.  
Conceptualization, Z.T.; Data curation, B.X.; Formal analysis, J.D.; Writing--original draft, B.X.; Writing--review & editing, B.X. and Z.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant number 52078058 and grant number 51478049; the Hunan Provincial Natural Science Foundation Project of China, grant number 2022 JJ50323 and grant number 14 JJ2075; the Major Technological Achievements Transformation Program of Hunan Strategic emerging industries of China, grant number 2017 GK4034; the Hunan Long-span Bridge Construction Technology and Assembly Engineering Technology Research Center of China, grant number 2018 TP2058.  
Not applicable.  
All data that support the findings of this study are available from the corresponding author upon reasonable request.  
The authors declare no conflict of interest.