Predictive Model of an Elastomer for Dynamic Properties under Thermal Environment Prof. Dooho LEE (Dongeui University)
In this paper, the variability of dynamic stiffness in an elastomer due to thermal aging is estimated using a degradation model and uncertainty quantification method. A degradation model introduced for the thermal aging also describes the variation of the material properties along time. A finite element model describes the dynamic characteristics of the elastomer. The variability of the predicted degradation under the quantified uncertainties is estimated using the double-loop eigenvector dimension reduction (EDR) method. The proposed method is applied to a mount as a numerical example.
Numerical evaluation of ABS parts fabricated by fused deposition modeling and vapor smoothing Prof. Sung-Uk ZHANG (Dong-Eui University)
Fused deposition modeling (FDM) is one of the popular 3D printing technologies due to an inexpensive extrusion machine and multi-material printing. However, FDM could only use thermoplastics such as ABS and PLA and has a problem related to the post-processing. In this study, the mechanical properties of ABS parts fabricated by FDM were measured. The ABS parts were divided into one with vapor smoothing process and the other without the vapor smoothing process which is one of the the post-processing methods. Using dynamic mechanical analysis (DMA) and dilatometer, temperature-dependent storage modulus and CTE for ABS specimens were observed. Based on the measured thermo-mechanical properties of ABS parts, finite element analysis was performed for an automotive bumper made of ABS. Moreover, response surface methodology was applied to study the relationship among design parameters of thickness of the bumper, ambient temperature, and application of the vapor smoothing process. In result, a design guideline for a ABS product could be provided without time-consuming experiments.
Development of a Mechanical Characterization Technique for Microand Nanoscale Polymer Thin-films Prof. Yun Young KIM (Dong-eui University)
A measurement technique for the mechanical characterization of micro- and nanoscale polymer thin-films was introduced in the present study. An experimental setup was established using an ultrasonic pulser that actuates a microcantilever so that material properties such as the Young’s modulus and shear modulus can be determined by detecting the resonant frequency shift upon coating of a thin-film to be evaluated using a laser interferometer. The present research proposes an evaluation method for the robust design of organic electronics and energy devices.
Development of degradation model of viscoelastic polymers during thermo-oxidative aging by Oberst beam testing Prof. Sun Yong KIM and DooHo LEE (Ulsan College, Dongeui University)
Depending upon the environmental conditions such as oxygen, ozone, sunlight, thermal, UV and radiation, the characteristic of viscoelastic polymer would be degraded. It is well known that oxidative degradation is generally considered to be the most serious problem for rubbers at high temperature. The prediction of their performance requires the knowledge of their dynamic properties as a function of frequency and temperature. In order to identify the characteristic of viscoelastic polymer during thermo-oxidative ageing, Oberst beam testing would be adopted. The aim of this research project is to identify the degradation characteristics of viscoelastic polymer by ageing at different properties and time period.