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In recent years, products that make use of integrated safety that use the environmental data to optimize occupant restraints have been on the market. Pre-safe system in the integrated safety category is an adaptive and smart protection system that utilizes the occupant information and the monitoring information on the accident prediction. These pre-safe systems need the proper algorithm corresponding to the crash scenario for the crash unavoidable state. Due to the crash scenario categories for the real world accidents is quite various, the development of the algorithm and the occupant protection system to reduce the injury is quite complex and costly. For this reason, a development process for pre-safe related integrated safety systems demands new tools based on the biomechanics to help design and assessment. The virtual development and assessment process with a viewpoint on the efficiency of the restraint development has been developed.

This paper is intended to find out the optimized restraint system for various crash conditions and to analyze the characteristics of those conditions numerically. 40km/h FF (Full Frontal crash), 56km/h FF and 64km/h ODB (Offset Deformable Barrier crash) conditions have been considered with 5th%ile female, 50th%ile male and 95th%ile male dummies on driver side. The vehicle lay out and crash pulses came from a compact passenger car. The restraint system was focused on the driver side airbag and seat belt. MADYMO 3D was used in this study for simulation.

The main role of CAB(side curtain airbag) is to protect the occupant's head in the event of side crash. The updated US NCAP for model year 2010 requires more extended coverage of CAB. It is not only required to cover the 50th%ile driver but also the 5th%ile driver and rear passenger. Although the general safety analysis model using only concerned sub-structure of the vehicle and prescribed structural motion is sufficient to handle frequent jobs, the analysis model with increased efficiency is needed when optimization is to be studied as it requires more runs and the model gets enlarged to consider extended sub-structure. In this study, three types of simplified analysis models are introduced. The first has an impactor which is composed of the head and neck with prescribed translational motions. It only uses the upper parts of the original sub-structure hence the run time is saved by 60∼70%.

Requirements of side curtain airbag have continued to increase. The revised SINCAP, FMVSS-226 ejection mitigation and small overlap of IIHS had added these requirements. To meet all the requirements, high inflator energy and complex cushion shape became necessary. Such situations increased possibility of cushion failure while deploying. Unfortunately, all the design verification tests are usually completed in a relatively latter stage of development and repetitive testing is needed to consider large dispersion of failure probability distribution. Therefore, verification and design improvement by numerical simulation in an early stage are desirable. A simulation method which can verify CAB deployment was developed in this study. The developed method has three distinct features. Firstly, nonlinear fabric materials and membrane finite elements are used to consider fracture of cushion fabric. Secondly, a pre-simulation procedure had been established.

Owing to an increasing autonomous emergency braking (AEB) adoption, emergency braking before crash occurs more often than in the case of conventional vehicles. Due to the sudden deceleration in AEB activation, passengers move forward before the crash. To explore how this forward movement affects passenger injury, sled tests are performed with an inclined dummy representing forward displacement. The test shows that a shorter distance between the airbag and passenger results in bigger neck injuries induced by airbag deployment force. A countermeasure is suggested to prevent neck injury in emergency braking situation by reducing deployment force and protrusion.

Gas leakage properties in numerical models of a SAB (Side Air Bag) need to be estimated without any component testing for a prompt simulation. A reasonable and accurate method for predicting leakage properties, which can be used in MADYMO simulations, is introduced in this study. Leakage functions were formulated with 9 assumptions and coefficients of functions are obtained based on information about components of SABs. The Information and the obtained coefficients were collected as a database. 29 types of drop tower tests were done to build this database. Four types of SABs were chosen and tested to validate the accuracy of the developed prediction method. The resulting correlations between simulations and tests turned out to be sufficiently accurate.

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.

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.

As occupant injuries induced by airbag deployment became a critical issue, revisions to FMVSS 208 were made to mandate the adoption of advanced airbag which can protect occupants of varying statures. As a result, OCS (Occupant Classification System) has become an important part of advanced airbag technologies. In this paper, we review existing OCS technologies briefly and list details of development issues and solutions for weight-based OCS. As an effort to reduce cost and optimize performance for the semi-LRD (Low Risk Deployment) airbag system, a study on reducing the number of sensors from 4 to 2 for the current system utilizing DFSS methodology is provided and discussed.

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.

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.

Recently, keen interest has been focused on the reduction of fuel consumption through the development of eco-friendly and weight-effective vehicles. This is due in part to the strengthening of regulatory standards for fuel efficiency in each country. This study will focus on the optimization of the IP (Instrument Panel) module, in particular, the cowl crossbar, which in some vehicles, can account for more than 33% of the IP module weight. The design objectives of the cowl crossbar were to use continuous fiber thermoplastic composite materials to achieve high stiffness, while optimizing the strength to weight performance as evaluated through vehicle sled and crash testing. This research will introduce the development and optimization methodology for an alternative material, which achieved about a 30% weight reduction as compared to steel.

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.

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.

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 role of CAB is protecting the passenger's head during rollover and side crash accidents. However, the performance of HIC and ejection mitigation has trade-off relation, so analytical method to satisfy the HIC and ejection mitigation performance are required. In this study, 3 types of CAB were used for ejection mitigation analysis, drop tower analysis and SINCAP MDB analysis. Impactor which has 18kg mass is impacting the CAB as 20KPH velocity at six impact positions for ejection mitigation analysis. In drop tower analysis, impactor which has 9kg mass is impacting the CAB as 17.7KPH velocity. Acceleration value was derived by drop tower analysis and the tendency of HIC was estimated. Motion data of a vehicle structure was inserted to substructure model and the SID-IIS 5%ile female dummy was used for SINCAP MDB analysis. As a result, HIC and acceleration values were derived by MDB analysis.