Full length articleDynamic response of internally nested hemispherical shell system to impact loading

- An INHSS composed of two hemispherical shells is proposed as an energy absorber.
- The dynamic behaviors of the INHSS were experimentally investigated.
- An experimentally validated finite element model is developed.
- Parametric studies are conducted using the established computational models.

The dynamic deformation behaviors of the internally nested hemispherical shell system (INHSS), were explored experimentally and computationally. Two specimens with different ratios of inner shell thickness δ to outer shell thickness Δ were tested in a drop weight machine. For the specimen with smaller δ/Δ, non-axisymmetric deformation mode occurred with a stable force platform and longer loading history, while for the specimen with larger δ/Δ, axisymmetric deformation was exhibited. Meanwhile, experimentally validated finite element model was employed to study the deformation mechanism after the critical point when the outer shell contacts with the inner shell based on the ratio of square of shell thickness to radius. Subsequently, parametric studies are conducted by varying governing factors, including thickness, radius and offset distance of the inner shell. Results show that the dynamic deformation process and energy absorption capability of the INHSS depends on the thickness and radius of the inner shell.