PSI - Issue 68

E. Ezgi Aytimur et al. / Procedia Structural Integrity 68 (2025) 540–546 / Structural Integrity Procedia 00 (2024) 000–000 E. Ezgi Aytimur

543

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Fig. 1. Impact simulation model

in the contact area between the deformable plate and the impactor with a contact sizing of 0.2 mm. The element type isQuad / Tri with a number of elements are 381551. Finally, the simulation is conducted using the SMP (Shared Memory Parallel) processing type with double precision to ensure increased accuracy in the results. At the end of the impact simulation, the results of total deformation, equivalent stress, directional velocity and acceleration are obtained.

3. Results and Discussion

Three di ff erent material models are observed and compared with each other according to results of impact simulations as seen in Table 2. The 10 mm diameter of sphere with a 16 m / sec velocity hit the deformable plate and deformation, equivalent stress, rebound acceleration (deceleration) were examined. Also, restitution coe ffi cient is evaluated as ratio of final and initial velocity.

Table 2. Simulation results Material Model

Deformation ( mm )

Equivalent Stress ( MPa )

Deceleration ( g )

1 . 7 × 10 5 1 . 5 × 10 5 1 . 2 × 10 5

Johnson Cook

0.133 0.148 0.197

394.4

Cowper Symonds

368

Elastic

180.6

In this study, the total deformation values occurring in the target material after a single impact were found to be 0.133, 0.148, and 0.197 mm for the Johnson-Cook, Cowper-Symonds, and Elastic material models, respectively. An illustration of the simulation is shown in Figure 2. These results necessitate a comparative analysis to discern the performance di ff erences among the models. The observed variations in total deformation can be attributed to the distinct constitutive behaviors encoded within each material model. The Johnson-Cook model incorporates parameters that account for strain rate sensitivity, rendering it capable of accurately capturing the material’s response to dynamic loading conditions. Consequently, its lower total deformation value suggests a more robust resistance to deformation under impact. Conversely, the Cowper-Symonds model, although widely used for its simplicity and computational e ffi ciency, may exhibit limitations in accurately representing the material’s response to high strain rates. This is evident in the slightly higher total deformation value obtained with this model compared to the Johnson-Cook model. The Cowper-Symonds model typically lacks parameters to capture thermal e ff ects and strain rate sensitivity adequately, which could contribute to its comparatively higher deformation. This is supported by the study of Zhang et al. (2023) on the material behavior of steel under high-strain rates and high temperatures. The study compares the Jonhson-Cook and Cowper-Symonds material models using experimental data and finds Johnson-Cook material model gives more