Case Study · Ref. 82

Oblique Impact on a Bolted Armor Plate Assembly

Explicit Dynamics FEAConfidential Details Removed

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Explicit dynamics stress contour of a projectile perforating two bolted steel plates — **Oblique Impact on Bolted Armor Plates — result**Projectile at 800 m/s perforating a two-plate Steel 4340 bolted assembly (Ansys Explicit Dynamics).

3D geometry of bolted armor plates and an oblique projectile — **Impact Study — geometry**Two bolted Steel 4340 plates with an oblique projectile.

Finite element mesh with refined impact zone on bolted plates — **Impact Study — refined mesh**Hexahedral mesh refined in the 40 mm impact zone.

Total deformation contour after projectile perforation — **Impact Study — total deformation**Total deformation at end time (0.15 ms).

Von Mises stress contour of bolted plates under impact — **Impact Study — equivalent stress**Peak von Mises stress 1.23 GPa at end time.

Equivalent plastic strain contour at the impact zone — **Impact Study — equivalent plastic strain**Maximum equivalent plastic strain 0.968, localised to the impact zone.

Impact animation frame 1 — **Impact sequence — frame 1**Projectile contact.

Impact animation frame 2 — **Impact sequence — frame 2**Penetration of the first plate.

Impact animation frame 3 — **Impact sequence — frame 3**Penetration of the second plate.

Impact animation frame 4 — **Impact sequence — frame 4**Full perforation at 0.15 ms.

Case study · Ref. 82 · EXPLICIT DYNAMICS

Oblique Impact on a Bolted Armor Plate Assembly

Challenge: Predict the damage to a two-plate Steel 4340 bolted assembly struck by a projectile at 800 m/s at an oblique angle.

Approach: Ansys Explicit Dynamics with element erosion, refined 40 mm impact-zone mesh and bolted-joint representation; deformation, stress and plastic-strain review over 0.15 ms.

Outcome: Full perforation of both plates within 0.15 ms; peak von Mises stress 1.23 GPa; maximum equivalent plastic strain 0.968, with damage localised to the impact zone.

Problem / Requirement

Predict the damage to a two-plate Steel 4340 bolted assembly struck by a projectile at 800 m/s at an oblique angle.

Engineering Scope

3D geometry of two bolted Steel 4340 plates with an oblique projectile

Hexahedral mesh refined in the 40 mm impact zone, with bolted-joint representation

Projectile initial velocity of 800 m/s and boundary conditions

Ansys Explicit Dynamics with element erosion over 0.15 ms

Total deformation, equivalent (von Mises) stress and equivalent plastic strain review

Four-frame impact sequence: contact, first-plate penetration, second-plate penetration, full perforation

Deliverables

FEA report with geometry, mesh, boundary conditions and material basis Deformation, stress and plastic-strain contour plots at end time Impact sequence frames Conclusions on perforation and damage extent

Client Value Delivered

Full perforation of both plates within 0.15 ms

Peak von Mises stress 1.23 GPa at end time

Maximum equivalent plastic strain 0.968, with damage localised to the impact zone

Standards Referenced

Ansys Explicit Dynamics (analysis basis) Project specification

Software Used

Ansys Workbench (Explicit Dynamics) Ansys SpaceClaim

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