Finite Element Analysis and Structural Weight Reduction of a CNG Cylinder Mounting Frame Using SIMP-Based Topology Optimization
Keywords:
CNG Cylinder Frame, SIMP Topology Optimization, Finite Element Analysis, ANSYS Workbench, Structural Weight Reduction, Principal Stress, Strain Energy, Commercial VehicleAbstract
The structural design of compressed natural gas (CNG) cylinder mounting frames for commercial vehicles demands a rigorous balance between weight efficiency and structural safety. This study presents a systematic finite element analysis (FEA) and topology optimization investigation of a 4×3 CNG cylinder support frame modelled in SolidWorks 2024 and analysed in ANSYS Workbench 2020 R2. The SIMP (Solid Isotropic Material with Penalization) method is used to minimize structural compliance at a target volume fraction of 0.60–0.70. An applied cylinder loading force of 8,000?N across 48 saddle faces, combined with Standard Earth Gravity (9,806.6?mm/s²), served as the primary load inputs. Fixed support boundary conditions were applied at four chassis mounting feet. Baseline FEA results revealed a maximum principal stress of 10.925?MPa, total strain energy of 312.2?mJ, and a maximum equivalent elastic strain of 1.5282×10???mm/mm. Following topology optimization at a converged volume fraction of 0.62, the frame achieved 37.7% mass reduction and 45.1% compliance reduction while maintaining a minimum safety factor of 22.3, well above the regulatory threshold of 2.0. The deformation increase was limited to 9.3%, within the 15% design acceptance limit. These results confirm that SIMP-based topology optimization is an effective tool for lightweight CNG frame design without compromising structural integrity.
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