Numerical and Experimental Investigation on the Effect of Geometric Discontinuity on Frequency Response of Composite Lattice Conical Structures

Subject Areas : Mechanical Engineering

M. R Zamani ^{1 *} , M Zaretabar ²

1 - Mechanical Engineering Department, Malek-Ashtar University of Technology, Tehran, Iran
2 - Mechanical Engineering Department, Malek-Ashtar University of Technology, Tehran, Iran

Received: 2022-07-17 Accepted : 2022-09-20 Published : 2022-12-01

Keywords: Composite lattice structure, Geometric discontinuity, Finite Element, Modal Analysis, Conical structure,

Abstract :

Composite structures are increasingly being used in various engineering structures such as automotive, aerospace, and civil structures due to their superior properties, namely, high strength-to-weight ratio, impact resistance, and durability. For the purpose of accessibility to other components and possibility of installation, aerospace structures encounters geometrical discontinuities which can lead to a complex structural analysis due to non-isotropic behavior. This paper aims to study the frequency response behavior of a composite lattice conical structure considering the effect of geometric discontinuity stiffened by a circular ring. The lattice structures are made of glass fiber reinforced polymers (GFRP) fabricated using filament winding method and cured in an autoclave. Numerical analysis and experimental modal testing was performed to obtain frequency response of the structures considering geometrical discontinuities. The results showed that the natural frequency values of structures with cutout in free-free boundary conditions are lower than those without cutout. Furthermore, comparing the mode shapes of structures indicated that these shapes were similar to each other and only some slight differences in discontinuity area were observed in some modes. Finally, the highest difference of numerical analysis results in structures with or without cutout was 2.61% while the highest difference of experimental analysis results in the structures was 3.73%. The greatest difference in the numerical and experimental analysis results is pertinent to the second mode in the structure without cutout is 15.64% and in the structure with cutout is 12.48%.

References:

1. Hemmatnezhad M., Rahimi G.H., Tajik M., Pellicano F., 2015, Experimental, numerical and analytical investigation of free vibrational behavior of GFRP-stiffened composite cylindrical shells, Composite Structures 120: 509-518.


2. Li Z.M., Qiao P., 2014, Nonlinear vibration analysis of geodesically-stiffened laminated composite cylindrical shells in an elastic medium, Composite Structures111: 473-487.


3. Lopatin A.V., Morozov E.V., Shatov A.V., 2016, An analytical expression for fundamental frequency of the composite lattice cylindrical shell with clamped edges, Composite Structures141: 232-239.


4. Khadem S.E., Nezamoleslami R., 2017, Investigation of the free vibrations of composite anisogrid lattice conical shells formed by geodesically spiral and circumferential ribs, International Journal of Applied Mechanics 9(4): 1750047.


5. Zhao J., Choe K., Shuai C., Wang A., Wang Q., 2019, Free vibration analysis of functionally graded carbon nanotube reinforced composite truncated conical panels with general boundary conditions, Composites Part B: Engineering 160: 225-240.


6. Wang B., Tian K., Zhou C., Hao P., Zheng Y., Ma Y., Wang J., 2017, Grid-pattern optimization framework of novel hierarchical stiffened shells allowing for imperfection sensitivity, Aerospace Science and Technology 62: 114-121.


7. Ahmadifar A., Zamani M.R, Davar A., Heydari Beni M., 2020, Experimental and numerical buckling analysis of carbon fiber composite lattice conical structure before and after lateral impact, Journal of Applied and Computational Mechanics 6(4): 813-822.


8. Hemmatnezhad M., Ansari R., Darvizeh M., 2014, Prediction of vibrational behavior of composite cylindrical shells under various boundary conditions, Applied Composite Materials 17: 225-241.


9. Zarei M., Rahimi G.H., Hemmatnezhad M., 2020, Free vibrational characteristics of grid-stiffened truncated composite conical shells, Aerospace Science and Technology 99: 105717.


10. Zarei M., Rahimi G.H., Hemmatnezhad M., 2021, On the free vibrations of joined grid-stiffened composite conical-cylindrical shells, Thin-Walled Structures161: 107465.


11. Zaretabar M., Zamani M. R., Parsa H., Heydari Bani M., 1400, Effect of geometric discontinuity on the strength of composite lattice conical structure under axial buckling, 29th Annual International Conference of Iranian Mechanical Engineers Association and 8th Power Plant Industry Conference, Tehran.


12. Zamani M.R., Zaretabar M., Parsa H., Heydari Beni M., 2021, Numerical investigation of the grid geometry effect on the modal response and buckling of grid-stiffened composite conical structure, ADMT Journal 14(4): 85-89.