Evaluation of surface and dimensional phenomena in punching of DP800 advanced strength steel utilising the Cockcroft-Latham Damage Model

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DEMİR B., Saier A. E., GÜRÜN H.

JOURNAL OF POLYTECHNIC-POLITEKNIK DERGISI, cilt.29, sa.4, 2026 (ESCI)

Özet

This study presents a quantitative and original investigation of the punching behaviour of DP800 advanced high-strength steel (AHSS), widely used in automotive components due to its high strength-to-weight ratio. Experimental tests on 1.5 mm thick DP800 sheets revealed a maximum true stress of similar to 900 MPa, accompanied by uniform elongation behaviour. Five distinct punch geometries were evaluated, among which the P16 punch produced the smoothest cutting surface and the lowest burr height (0.08 mm), while the flat punch yielded 0.11 mm. Finite element simulations performed using the Cockcroft-Latham (C-L) damage model confirmed a critical damage constant of C = 1.5, which agrees with the experimental results. The shear zone accounted for approximately 28% of the total sheet thickness, and dimensional accuracy measurements indicated that the P16 punch achieved hole diameters closest to the nominal 20 mm. Unlike previous studies that primarily focused on the general behaviour of AHSS, Athis work provides a detailed quantitative analysis of DP800 punching mechanics and surface quality. The findings deliver novel insights into tool-geometry optimisation and damage prediction, offering practical guidelines for improving manufacturing precision and process reliability in AHSS forming operations.