Ansys Application Enables 3D Structural Analyses
SMC has appointed Idac to develop a macro that will allow SMC engineers to predict the deflections and stresses seen by the telescopic communication masts the company manufactures. SMC is regularly required to design and manufacture telescopic communication masts, which are customised to handle customer-specified load configurations. The deflections of the mast must be kept within a very tight tolerance for proper operation.
Stresses also need to be kept within specified limits. SMC required an automated procedure to analyse different design configurations based on a number of predefined design variables under a given set of loads. This would require a set of input design variables to be supplied by a 'user' to the Ansys software, which would then create the Finite Element (FE) Model to be analysed, solve the FE Model and post-process the results into a set of text files and graphical plots for final assessment by SMC.
Idac was required to develop a macro that would allow SMC engineers to predict the deflections and stresses seen by the communication masts they manufacture. The project to create this automatic procedure was split into the following phases: generation of the parametric Ansys macro; generation of the design variables input file; and generation of the automatic post-processing macro. A macro to generate the parametric model was written, so that a model consisting of a set of concentric tubes overlapping at the ends would be created in the Ansys software for analysis.
Examples of the variables required for input by the SMC engineers for each tube were as follows: length; thickness; diameter; and overlap distance. Each mast tube also had the option of being guyed. The tube guy sets could be either three or four guy rope arrangements. The guy ropes could be solid (where tension and compression could be supported) or cable-like (supporting tension only). The geometry was meshed with 1D pipe elements, element type Pipe16 and the guys were meshed with either Link8 (tension and compression) or Link10 (tension only) elements.
The overlapping of the tubes was modelled with coupling restraints between the tubes. A 3D nonlinear (large deflection) structural analysis was carried out. The mast will be fixed at its base and the free ends of the guys will also be fixed. The guys, if defined, were specified an initial pretension load. External loads can be defined as follows: horizontal and vertical point loads at the top of the mast with an offset axial torque applied at the top of the mast; internal pressure in mast; and wind pressure applied up the mast (defined by SMC based on an equation dependent on height).
Material input was required for each tube; this consisted of Young's Modulus, Poisson's Ratio and failure criteria for safety factor calculations. The post-processing procedure was automated by means of a macro. Running of the macro generated a tabulated text file containing the tip deflection, the deflected angle and safety factors, as well as all the input variables. A set of stress plots was also created. The figures to the left and right show typical deflection and stress plot graphical outputs.
Idac has created an Ansys application for SMC enabling its engineers and project managers to run full and rapid 3D nonlinear (large deflection) structural analyses, by entering mast parameter values as prompted. The application extends the use of Ansys structural analysis software within SMC to a rapid assessment tool allowing them to access the impact of various customer-driven loading scenarios on proposed mast configurations. This capability will improve SMC's ability to recommend the most reliable, safe and economical mast arrangements to satisfy the customer's various 'in-field' requirements in the shortest possible time.
This makes SMC's engineering and sales department more responsive to design requirements and/or requests by clients to assess the impact of changes to the payloads imposed on an existing mast.
Stresses also need to be kept within specified limits. SMC required an automated procedure to analyse different design configurations based on a number of predefined design variables under a given set of loads. This would require a set of input design variables to be supplied by a 'user' to the Ansys software, which would then create the Finite Element (FE) Model to be analysed, solve the FE Model and post-process the results into a set of text files and graphical plots for final assessment by SMC.
Idac was required to develop a macro that would allow SMC engineers to predict the deflections and stresses seen by the communication masts they manufacture. The project to create this automatic procedure was split into the following phases: generation of the parametric Ansys macro; generation of the design variables input file; and generation of the automatic post-processing macro. A macro to generate the parametric model was written, so that a model consisting of a set of concentric tubes overlapping at the ends would be created in the Ansys software for analysis.
Examples of the variables required for input by the SMC engineers for each tube were as follows: length; thickness; diameter; and overlap distance. Each mast tube also had the option of being guyed. The tube guy sets could be either three or four guy rope arrangements. The guy ropes could be solid (where tension and compression could be supported) or cable-like (supporting tension only). The geometry was meshed with 1D pipe elements, element type Pipe16 and the guys were meshed with either Link8 (tension and compression) or Link10 (tension only) elements.
The overlapping of the tubes was modelled with coupling restraints between the tubes. A 3D nonlinear (large deflection) structural analysis was carried out. The mast will be fixed at its base and the free ends of the guys will also be fixed. The guys, if defined, were specified an initial pretension load. External loads can be defined as follows: horizontal and vertical point loads at the top of the mast with an offset axial torque applied at the top of the mast; internal pressure in mast; and wind pressure applied up the mast (defined by SMC based on an equation dependent on height).
Material input was required for each tube; this consisted of Young's Modulus, Poisson's Ratio and failure criteria for safety factor calculations. The post-processing procedure was automated by means of a macro. Running of the macro generated a tabulated text file containing the tip deflection, the deflected angle and safety factors, as well as all the input variables. A set of stress plots was also created. The figures to the left and right show typical deflection and stress plot graphical outputs.
Idac has created an Ansys application for SMC enabling its engineers and project managers to run full and rapid 3D nonlinear (large deflection) structural analyses, by entering mast parameter values as prompted. The application extends the use of Ansys structural analysis software within SMC to a rapid assessment tool allowing them to access the impact of various customer-driven loading scenarios on proposed mast configurations. This capability will improve SMC's ability to recommend the most reliable, safe and economical mast arrangements to satisfy the customer's various 'in-field' requirements in the shortest possible time.
This makes SMC's engineering and sales department more responsive to design requirements and/or requests by clients to assess the impact of changes to the payloads imposed on an existing mast.
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