numerical and experimental investigation on the effect of geometric discontinuity on frequency response of composite lattice conical structures

Composite structures are increasingly being used in variousengineering structures such as automotive, aerospace, and civilstructures due to their superior properties, namely, high strength-toweightratio, impact resistance, and durability. for the purpose ofaccessibility to other components and possibility of installation,aerospace structures encounters geometrical discontinuities which canlead to a complex structural analysis due to non-isotropic behavior.this paper aims to study the frequency response behavior of acomposite lattice conical structure considering the effect of geometricdiscontinuity stiffened by a circular ring. the lattice structures aremade of glass fiber reinforced polymers (gfrp) fabricated usingfilament winding method and cured in an autoclave. numericalanalysis and experimental modal testing was performed to obtainfrequency response of the structures considering geometricaldiscontinuities. the results showed that the natural frequency values ofstructures with cutout in free-free boundary conditions are lower thanthose without cutout. furthermore, comparing the mode shapes ofstructures indicated that these shapes were similar to each other andonly some slight differences in discontinuity area were observed insome modes. finally, the highest difference of numerical analysisresults in structures with or without cutout was 2.61% while thehighest difference of experimental analysis results in the structureswas 3.73%. the greatest difference in the numerical and experimentalanalysis results is pertinent to the second mode in the structure withoutcutout is 15.64% and in the structure with cutout is 12.48%.