Investigations on formability of tailor laminated sheets in single point incremental forming

Abstract

In this article, formability of tailor laminated sheets in single point incremental forming (SPIF) is investigated using forming limit curve (FLC) and maximum formable wall angle determined theoretically and incremental sheet forming tests. Two different sheet materials namely aluminum alloy AA5083 and polycarbonate were laminated in two different configurations, that is, AA5083/PC, and AA5083/PC/AA5083. FLCs were determined for the laminated sheets using deformation instability method and compared to that of the base sheets. It was observed that formability of the laminated sheets was higher than that of the PC and AA5083 sheets for plane strain case. The maximum formable wall angle was determined by varying the wall angle till the onset of fracture through deforming the sheet into square pyramid shapes. Deformation depths at the onset of fracture for the incrementally formed laminated sheets got decreased with the increase of forming wall angle. Optical macrographs of the cross-sections of the deformed laminated sheets with maximum forming wall angles were taken, and variations of sheet thicknesses along the center line of the deformed sheets were compared for the different cases. Higher triaxiality of AA5083/PC/AA5083 sheet results in lower formability compared to AA5083/PC sheet obtained from membrane analysis. Formation of bump structure due to delamination during SPIF of laminated sheets could be avoided using proper selection of tool path.

Precepts for Designing Sandwich Materials

“…This way, ISF allows the possibility of shaping sheets into complex forms, which can open the possibilities of MPM SMs in biomedical, aeronautical, and various other fields [106][107][108]. In recent studies, the formability of MPM SMs has been found to be better via ISF as compared to conventional sheet forming techniques like deep drawing [109,110]. However, the forming potential of MPM SMs is found to be 30-50% of the same-sized sheet made completely of metallic skin [111,112].…”

Minimizing the Main Strains and Thickness Reduction in the Single Point Incremental Forming Process of Polyamide and High-Density Polyethylene Sheets

“…Of particular interest with regard to forming processes in general and SPIF in particular is the influence of the process parameters on the main strains and thickness reduction [ 7 , 8 ]. Knowing the strain distribution also allows the evaluation of the failure mode in incremental forming and, implicitly, the determination of formability [ 9 ].…”

Groove stiffening of sheets by single point incremental forming

“…This paper explores the potential of single-point incremental forming (SPIF) to locally emboss stiffening grooves in thin panels using a single clamping (Figure 1(c)) as it was originally proposed by Slota et al 9 and previously utilized by Lu et al 10 to evaluate friction between the forming tool and panels. The possibility of performing the forming and stiffening stages simultaneously combined with the dieless characteristics of SPIF 11 leads to greater flexibility and economic benefits than those currently offered by conventional reinforcement by stringers.…”