Numerical Simulation and Parametric Investigation ofIncremental Sheet Forming Process for MultilayerSandwich Panels

Abstract

The multifunctional structure, i.e., multilayer sandwich panel (MLSP), exhibits properties like high rigidity, good specific strength, and lightweight and thermal resistance. Structural performance is attributed to these properties, making MLSP very favourable for producing highly reliable structures and increasing fuel efficiency due to its lightweight structure. Forming MLSP through conventional forming techniques such as deep drawing and punching is very challenging because it not only limits the formability but also requires special tooling and produces other undesirable effects. This work researched the feasibility of MLSP's formation through the single-point incremental sheet forming (SPIF) process. The SPIF process was modelled in the LS-DYNA to form MLSP into a benchmark shape. A tensile test was performed to evaluate the mechanical properties of the AL-1050. In the simulation, six more cases were also evaluated to see the effects of tool diameter, feed rate, and step size on the forming forces, formability, maximum percent thinning, etc. CATIA software generated the numerical code (NC) for the constant Z-level tool path and fed it to the CNC machine to perform the SPIF experiment on the MLSP. The larger tool diameter contributed to smaller forming forces, good formability, and less fracture area. The crack area and wrinkling tendency increase with the increase in feed rate first and then decrease with a further increase in feed rate. There was good agreement between the simulated and experimental formed geometrical shapes, proving that SPIF is feasible for forming multilayer sandwich structures.

Keywords

• Forming limit diagram
• formability
• multilayer sandwich panel
• single point incremental forming