On the Determination of Forming Limits in Polycarbonate Sheets
|Author||Sainz, Ana Rosa
Centeno Báez, Gabriel
Silva, María Beatriz
López Fernández, José Andrés
Martínez Donaire, Andrés Jesús
Vallellano Martín, Carpóforo
|Department||Universidad de Sevilla. Departamento de Ingeniería Mecánica y de Fabricación|
|Abstract||By proposing an adaptation of the methodology usually used in metal forming, this paper
aims to provide a general procedure for determining the forming limits, by necking and fracture,
of polymeric sheet. The experimental ...
By proposing an adaptation of the methodology usually used in metal forming, this paper aims to provide a general procedure for determining the forming limits, by necking and fracture, of polymeric sheet. The experimental work was performed by means of Nakajima specimens with di erent geometries to allow to obtain strains in the tensile, plane, biaxial and equibiaxial states for Polycarbonate sheet with 1 mm of thickness. The application of the time-dependent and flat-valley approaches used in metals has been revealed appropriate to characterize the onset of necking and obtain the forming limits of polycarbonate, despite the stable necking propagation typical of polymeric sheets. An analysis of the evolution of the strain paths along a section perpendicular to the crack allowed for a deeper understanding of the steady necking propagation behaviour and the adoption of the methodology of metals to polymers. The determination of the fracture strains was enhanced with the consideration of the principal strains of the DIC system in the last stage, just before fracture, due to the significant elastic recovery typical of polymeric sheets. As a result of this analysis, accurate formability limits by necking and fracture are obtained for polycarbonate sheet, together with the principal strain space, providing a general framework for analysing incremental sheet forming processes where the knowledge of the fracture limits is relevant.
|Funding agencies||Gobierno de España
Fundação para a Ciência e a Tecnologia. Portugal
UIDB / 50022/2020
|Citation||Sainz, A.R., Centeno Báez, G., Silva, M.B., López Fernández, J.A., Martínez Donaire, A.J. y Vallellano Martín, C. (2020). On the Determination of Forming Limits in Polycarbonate Sheets. Materials, 13 (4), Article number 928.|