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The effects of pad properties and thermal coning of discs on high speed judder were investigated using dynamometer and vehicle tests. The friction materials of different thermal conductivities were manufactured and the discs were design-modified to control the thermal coning during braking under high speed conditions. Brake Torque Variation(BTV) was measured to evaluate the judder propensity in the dynamometer tests and the vibration on steering wheel and brake pedal was measured in the vehicle tests. The results showed that the increase of thermal conductivity of pad could not affect the judder propensity during high speed braking below 350°C of disc temperature, however better disc design reduced judder propensity due to the lower thermal deformation. Moreover, the increase of pad compressibility can reduce judder propensity due to the increase of damping capacity.

The instrument panels are made to meet stiffness requirements and also interior safety regulation such as head impact test. Nowadays, CAE is widely used to predict the test results in advance. However, considering fracture phenomena, the characteristics of material takes a significant role for the simulation of the real tests. In this paper, high speed tensile tests and fracture tests of specimens representing typical stress-states were performed to make a fracture criterion of a plastic material (PC/ABS). The suggested method was validated by comparing simulation with test results.

Ar plasma treatment was carried out to reduce the sheet resistance of indium tin oxide (ITO) thin films. To verify how the concentration of oxygen vacancies in the film increased with the Ar plasma treatment time, cumulative and continuous plasma treatments were conducted. In addition, to improve the transmittance and reduced the sheet resistance the PDMS layer was as a stamp on the surface of ITO. The oxidation of the PDMS stamp appears to be a key factor to improve the characteristics of ITO thin film. Furthermore, an indium-tin-oxide (ITO) thin film with approximately 50 nm thickness was successfully synthesized on glass substrates by using a fully aqueous sol-gel process. The annealing temperature and argon plasma treatment time appear to be key factors in reducing resistivity and increasing the transmittance of the thin film.

Optimal Composition of Light-weight BMC (Bulk molding compound) for automotive headlamp reflector using Glass bubble was investigated. Glass bubble (G/B) normally has low heat conductivity which has a bad influence on cycle time making products like reflectors. It was very important to improve the productivity of Light-weight BMC by means of finding optimal composition of base resin, curing agent and other additives. This study focused on the ideal ratio of each component of BMC, unsaturated polyester resin, glass bubble, inorganic filler, glass fiber and additives. Mechanical and environmental properties of the product which was made of optimized light-weight BMC were evaluated to compare with the properties of the product which was made of existing BMC.

ABS assembly is supported by the mounting bracket which is installed at the body inside engine room. Such feature of the mounting bracket requires consideration of durability performance under the dynamic random loads imposed by engine excitation. So, modal parameters, such as natural frequencies and mode shapes, of ABS assembly and its bracket should be considered when evaluating the fatigue life. Therefore, fatigue analyses and experiments of ABS assembly and its bracket were performed in the frequency domain rather than the time domain. After that, analysis results were compared and correlated with experimental results, and the analysis method was updated to improve analysis accuracy.

Many automotive companies have recently introduced Virtual Product Development (VPD) techniques. The VPD helps engineers to reduce the number of design changes, speed up development time and improve product quality by utilizing CAE early in the design cycle before prototypes are ever created. In the VPD environment, however, simulation engineers inevitably perform a large number of analyses due to a number of design changes and validations of performance and reliability. In effect, the engineers have to follow many steps of analysis processes when using various kinds of simulation applications, which may require repetitious manual works such that it is easy to make mistakes. In an effort to solve these problems, automation software incorporating various types of analysis processes for automotive suspension components, DAAS (Durability Analysis Automation System) has been developed.

It is widely believed or speculated that higher pad compressibility leads to reduced brake squeal and that caliper design can affect brake squeal. After encountering anecdotal contradictory cases, this investigation was undertaken to systematically generate basic data and clarify the beliefs or speculations. In order to adjust pad compressibility, it is common to modify pad molding temperatures, pressures and times, which in addition to changing the compressibility, changes friction coefficient and physical properties of the pad at the same time. In order to separate these two effects, NAO disc pads were prepared under the same molding conditions while using different thicknesses of the underlayer to achieve different compressibilities, thus changing the compressibility only without changing the friction coefficient and physical properties of the pad.

We performed numerical analyses using an explicit code to evaluate the cumulative impact damage of an automotive front-end bumper during low-speed crash events, as described by CMVSS215. The CMVSS215 regulation consists of a series of test cases for the same parts. To evaluate the crash performance of a bumper, we used a coupled numerical analysis scheme and considered several matters such as the removal of residual vibrations and the evaluation of the bumper back beam recovery. We also used an EWK rupture model in the PAM-CRASH code to improve our damage and fracture estimates. Tensile test experiments were conducted to tune the performance of the EWK rupture model; the resulting material properties and fracture criterion were incorporated into the numerical analyses of the low-speed frontal crash events. The coupled analysis scheme was verified by comparing the output with bumper impact test data.

Since the environmental problems and new stricter regulations are forcing the industries to introduce more ecological materials for their products, biodegradable materials have attracted increasing attention. Among these materials, Polylactic acid (PLA) is remarkable for its modulus, strength, chemical resistance. However, PLA could not be used for automobile industries for its low heat resistance and impact strength. Therefore, in this study natural fiber was introduced as reinforcements in order to improve the properties of PLA. And for various experiments, Polypropylene (PP) was used as matrix resin instead of PLA. Especially for improving the properties of PLA composites, surface treatments, annealing, and adding rubber elements were performed. With surface treatments, we found that the mechanical properties of composite were improved. And with annealing treatment, we found the remarkable increase of heat resistance of PLA composite.

Corrosion stiction at the contact interface between a brake friction material and a gray iron disc under the parking brake condition was investigated by evaluating the possible parameters that affect the shear force to detach the corroded interface. Using production brake friction materials, comprising non-steel and low-steel types, corrosion tests were carried out by pressing the brake pad onto the gray iron disc using a clamp at various conditions. Results showed that the shear force to detach the corroded interface tended to increase with applied pressure and corrosion time. On the other hand, porosity, acidity, and hydrophobicity of the friction material did not show a reliable correlation to the stiction force. The poor correlation of the stiction force with the friction material properties indicated that the stiction force was not determined by a single factor but governed by multiple parameters including surface contact areas and inhomogeneity of the ingredients.