Die sheet hydroforming of a complex shaped AA2024-W Aircraft skin panel – from concept to final component

Serfontein, Jean-Pierre Louis (2021-03)

Thesis (MEng)--Stellenbosch University, 2021.

Thesis

ENGLISH ABSTRACT: Blanks and press tools are traditionally manufactured by conceptualising a design based on knowledge and experience. Designs are compensated through a "trial-and-error” process until the manufacturing solution has been validated. The use of manufacturing simulations has aided engineers to design and manufacture components. Simulated manufacturability studies are becoming standard practice worldwide. The purpose of this research is to evaluate and validate the simulation of die sheet hydroforming of a complex-shaped aluminium alloy aircraft skin panel. The capability of ESI Group’s PAM-STAMP 2G forming simulation software package and the procedure used in taking a component from concept to a realised part were assessed. A case study was conducted to evaluate and validate the simulation. The objective was to conceptualise the sheet metal blank and tooling and characterise the sheet metal blank material properties. Then, using simulation, the feasibility, and then manufacturability of the blank and tool concepts were evaluated. Finally, the concept was validated by manufacturing and inspecting the component. These steps defined the forming process conceptualisation cycle. ESI Group PAM-STAMP 2G was validated in a quantitative before-and-after field experiment. From the case study, several concepts were developed and evaluated digitally using the forming process conceptualisation cycle. Nine concepts were conceptualised. The final concept was selected for manufacturing and tool proofing. Four components were manufactured and inspected using standard metrology methods on a coordinate measuring machine.The components were found to meet the design requirements. The simulation process did not account for an installation condition; hence the unclamped inspection configuration was used. A lack of correlation between the simulation result and the manufactured components were found and required further investigation. An added simulation operation stage improved the alignment of the simulation result and the nominal surface, in turn,improved inspection within the simulation package. A slight improvement in the correlation between the simulation and the manufactured component was found. A simulation model validation study was conducted with a friction study to determine the dependency of the system on this parameter. The validation study showed a better correlation of the simulation result to the manufactured component at a higher friction coefficient. The friction coefficient was varied from 0.15 to 0.55, with 0.5 the best performing result. The four components were three-dimensional (3D) scanned and assessed using 3D metrology methods. The final surface profile deviation between the simulation and the manufactured component was 7.18 mm. The findings of this study showed two gapsin the simulation of die sheet hydroforming of complex-shaped panel-type aluminium alloy components. The omission of friction physics of the rubber-to-metal interface as the simulation under predicts distortion. Second is the lack of effective metrology inspection methods for assessment of the final predicted shape of the component within a commercial simulation software package.

AFRIKAANSE OPSOMMING: Raadpleeg teks vir opsomming

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/109870
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