Finite element simulation of thermoforming processes for polymer sheets

Warby, M. K.; Whiteman, J. R.; Jiang, Wenguang; Warwick, Peter; Wright, Thomas W.

doi:10.1016/s0378-4754(02)00077-0

Cited by 77 publications

(38 citation statements)

References 10 publications

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“…The formed part is then trimmed from the sheet. 1,2 Thermoforming is one of the most versatile and economical processes available for manufacturing returnable packaging and many other products. However, obtaining a uniform thickness of the final product with thermoforming is difficult.…”

Section: Introductionmentioning

confidence: 99%

A study on control of heater power and heating time for thermoforming

Xuan

et al. 2010

Int. J. Precis. Eng. Manuf.

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NOMENCLATUREC P =specific heat of ABS sheet, J/kg.K H=thickness of total sheets, m h=heat transfer coefficient, W/m 2 .K k=thermal conductivity of ABS, 0.174 W/m.K k eq =thermal conductance, W/m.K L=half of the total thickness, m N=total number of sheets q in =inputted heat flux, W/m 2 R c =contact resistance, m․ K/W T a =average temperature, K T c =center temperature, K T s =surface temperature, K T 0 =initial temperature, K T ∞ =environmental temperature, K t=time, s t h =heating time, s ρ=density of ABS sheet, 1050 kg m -3 α=thermal diffusivity of ABS, m 2 /s η n =eigen valueObtaining a uniform thickness of the final product using thermoforming is difficult, and the thickness distribution depends strongly on the distribution of the sheet temperature. In this paper, the time-dependent temperature distribution of the total sheets in the storing stage was studied because the temperature after the storing stage is the initial temperature of the heating process. An analytic solution for simulating the storing stage was derived. Using the solved analytic solution, the time-dependent temperature distribution of the total sheets was found out under the condition of assuming that the temperature-dependent specific heat of the ABS sheets was a certain constant value. Finally, the control method for a successful thermoforming using the heater power or heating time was researched in order to improve the quality of the final products. The results show that the satisfied temperature distribution can be obtained by adjusting the heater power or heating time. The method for analysis in this study will be used to improve the quality of the final products.

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Section: Introductionmentioning

confidence: 99%

A study on control of heater power and heating time for thermoforming

Xuan

et al. 2010

Int. J. Precis. Eng. Manuf.

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“…The composite manufacturing process involves large displacements and rotations and large shear of weft and warp fibres, which can have a significant effect on the processing and structural properties of the finished product. The formulation of new and more efficient numerical models for the simulation of the shaping composite processes must allow for reduction in the delay in manufacturing of complex parts and an optimization of costs in an integrated design approach [7,[18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Mechanical and geometrical approaches applied to composite fabric forming

2010

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In this paper, we are interested in the forming of composite fabric by deep-drawing. Two approaches (geometrical and mechanical) are proposed for the simulation of the composite fabric forming. The geometrical approach is based on a fishnet model. It is well adapted to preliminary design phase and to give a suitable estimate of the resulting flat patterns. The mechanical approach is based on a mesostructural approach. It allows us to take into account the mechanical properties of composite fabric (fibres and resin) and the various dominant modes of deformation of fabrics during the forming process. During simulation of composite fabric forming, where large displacement and relative rotation of fibres are possible, severe mesh distortions occur after a few incremental steps. Hence an automatic mesh generation with remeshing capabilities is essential to carry out the finite element analysis. Some numerical simulations of forming process are proposed and compared with the experimental results in order to demonstrate the efficiency of the proposed approaches.

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“…The composite manufacturing process involves large displacements and rotations and large shears of weft and warp fibres, which can have a significant effect on the processing and structural properties of the finished product. The formulation of new and more efficient numerical models for the simulation of the shaping composite processes must allow for reduction in the delay in manufacturing of complex parts and an optimization of costs in an integrated design approach [2]. In this study, a meso-structural approach for finite deformations and geometrical non-linearity is used to simulate the forming of composite fabrics.…”

Section: Introductionmentioning

confidence: 99%

Adaptive Remeshing of Composite Fabrics During the Forming Process

2010

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Continuous fibre reinforced composites are now firmly established engineering materials for manufacturing of components in automotive and aerospace industries. In this study, we propose a new approach to simulate the deformation of composite fabrics. A bi-component finite element based on an association of 3D membrane finite elements and truss finite elements is used to represent warp and weft fibres behaviour. During the simulations of the forming process, severe shear of fibres occurs due to the large displacements. It is then necessary to remesh the part to carry out the finite element analysis. This paper presents the remeshing method allowing refining and coarsening the mesh of the composite structure subjected to large displacement.

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Finite element simulation of thermoforming processes for polymer sheets

Cited by 77 publications

References 10 publications

A study on control of heater power and heating time for thermoforming

A study on control of heater power and heating time for thermoforming

Mechanical and geometrical approaches applied to composite fabric forming

Adaptive Remeshing of Composite Fabrics During the Forming Process

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