轴径双向电磁力协同驱动的翻边方法OA

Conventional uniaxial flanging processes for aluminum alloys face a fundamental trade-off:they achieve insufficient forming height at large flanging coefficients,while risking edge fracture at small coefficients.This limitation severely restricts their application in manufacturing high-performance,lightweight components.The underlying cause lies in the constrained material flow induced by uniaxial loading,which results in excessive thinning at the hole edge and makes it difficult to achieve both sufficient flanging height and good forming quality. To address this challenge,this study proposes a novel electromagnetic-driven flanging method based on the synergistic excitation of dual coils,which generate axial and radial electromagnetic forces,respectively.The axial force provides the primary driving force for forming,while the radial force actively directs material from the flange into the die cavity.An electromagnetic-mechanical coupled model was established using LS-DYNA to simulate this bidirectional force-based flanging process.A corresponding experimental prototype with dual pulsed power supplies and dual coils was also developed,enabling a comparative investigation of electromagnetic-driven flanging under both uniaxial and axial-radial bidirectional configurations. Comprehensive numerical simulations and experimental tests were conducted to evaluate the deformation behavior and flanging performance of AA5052-O aluminum alloy sheets with preformed holes.The results reveal that although the bidirectional process does not alter the stress-strain state at the hole edge,it effectively enhances material flow in the flange area,leading to a significant increase in wall height.Building on this finding,a novel forming strategy is proposed to improve the flanging limit:a larger flanging coefficient is selected to ensure edge quality,while radial electromagnetic force is introduced to enhance material flow into the flanging zone.This approach successfully resolves the inherent conflict in conventional uniaxialprocesses between achieving greater height and controlling edge thinning.The final results demonstrate that the proposed strategy achieves a 72.95%increase in flanging height at a flanging coefficient of 0.702 compared to uniaxial loading,and maintains a 31.04%improvement even against a uniaxial process with a lower coefficient of 0.602. A mechanistic analysis further clarifies the influence of discharge voltage and timing for both coils on flanging performance.Appropriate discharge matching is key to leveraging electromagnetic synergy.Specifically,with a constant radial coil voltage,flange flow initially increases and then decreases as the axial coil voltage rises.When the axial coil voltage is held constant,flange flow increases with higher radial coil voltage.In terms of discharge timing,moderately advancing the radial coil discharge(by approximately 250 μs)under the experimental conditions helps utilize the complementary effects of radial electromagnetic force and punch-driven material flow across different stages.This enhanced material flow capability contributes to the increased flanging height. Looking ahead,future work should further investigate the coupling mechanisms of blank-holder force,axial force,and radial force on flanging performance.Meanwhile,for local flanging applications on large flat or curved aluminum alloy sheets,focused research on axial-radial bidirectional electromagnetic force design and process parameter optimization is needed to advance this technology and its practical engineering applications.