Date of Award
5-2020
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Mechanical Engineering
Committee Chair/Advisor
Dr. Gregory Mocko, Committee Chair
Committee Member
Dr. Lonny Thompson
Committee Member
Dr. Srikanth Pilla
Committee Member
Dr. Garrett Pataky
Abstract
The overarching objective of this research is to develop a finite element model for simulation of the single point incremental forming (SPIF) process at different temperatures including convective heat assisted SPIF (CHASPIF). Single point incremental forming (SPIF) is a flexible manufacturing process with low tooling costs and times compared to thermoforming and die forming, for low production volumes. Convective heat assisted single point incremental forming (CHASPIF) is a variant of the SPIF process in which an external hot air source is used to heat the region surrounding the tool to improve formability, which can be assessed either in terms of the maximum strain or forming angle at the point of material failure. Currently, experimental testing is required to evaluate the feasibility of manufacturing using the CHASPIF process. An alternative to this involves the use of simulation models. Simulation models exist for room temperature polymer SPIF, but not for elevated temperature forming. In this work, a coupled thermomechanical finite element model is presented which can simulate room temperature SPIF and CHASPIF.
The simulation model is developed using ANSYS CAE through three parts: a) presentation of SPIF setup in FEA with proper boundary conditions b) simulation of convective localized heating from the external heat source, c) simulation of the temperature dependent material behavior, and the integration of all three parts. The temperature dependent material properties are modeled using the Three Network model and implemented in ANSYS through the PolyUmod library. The localized heating is modeled by applying a distribution of convective heat transfer coefficients which are experimentally iii evaluated. The model is tested for forming a conical frustrum and linear deformation. Results show that this model is able to predict the temperature within ± 5ºC and deformation with a 17% normalized root mean square error indicating medium accuracy. The model also correctly predicts a reduction in stress, forming forces and increase in the strain for CHASPIF compared to room temperature SPIF, in agreement with past work. The results from this model can be used for failure prediction and for evaluating the feasibility of using CHASPIF. In the future, this model will be integrated into a CAE tool for improved process planning of the SPIF process.
Recommended Citation
Kulkarni, Shubhamkar, "A Model for Simulation of Convective Heat Assisted Single Point Incremental Forming of Thermoplastics" (2020). All Dissertations. 3860.
https://open.clemson.edu/all_dissertations/3860
