• Proceedings of the ESK Conference
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• 1997.04a
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• pp.10-16
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• 1997

The ride comfort is one of the most important indices which decide the quality of automotive seats. A subjective evaluation is the general method for comfort evaluation of automotive seats. But the subjective evaluation assess the individual sensibility using questionnaire. Therefore, a need to develop methodologies to obtain objective measurements of the fatigue evaluation is evident. In an effort to monitor muscle activity during driving electromyography (EMG) was employed. In an experimental setting the subjective evaluation was conducted using questionnaire under the static conditions (8 subjects) and the fatigue was induced in muscles using EMG under the dynamic conditions (2 drivers). The resultant EMG signals were then sampled for three different muscles. In test involving 2 subjects of similar size and build, utilizing four different automotive seats, test results support the use of EMG to quantify muscular fatigue as a viable means of objective evaluation for the different automotive seats.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.9
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• pp.4518-4540
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• 2019

With the development of IT convergence technology, autonomous driving has gradually developed; however, the vehicle is still operated by the driver, who should always be in good health - but sometimes, this is not the case. It is especially dangerous to drive when drowsy, and unable to fully concentrate on driving, such as when taking certain medicines, or through fatigue. Drowsy driving is at least eight times more dangerous than normal driving, and as dangerous as drunk driving. Previous research has looked at technology to detect drowsiness, in order to wake up drivers when necessary, or to safely stop the vehicle. Furthermore, many studies have been conducted to find out when drowsiness occurs. However, it is more desirable for the driver to take sufficient rest during a break, in order to be able to continue to focus and drive. In other words, it is important to maintain a normal state before drowsiness. In this study, we introduce a sound source to increase driver concentration and prevent drowsiness, another that can improve the quality of sleep, and a system that produces these sound sources. The proposed system has a noise reduction effect of about 15 dB. We have confirmed that the proposed sound induces an EEG of the desired form.

• Science of Emotion and Sensibility
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• v.4 no.1
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• pp.53-60
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• 2001

As a part of HMS(Human-Machine System), the car is very important thing in common life. It is also a significant part to study on the controllers of car that is intentively related with all sensibilities during driving. There are lots of controllers on seating buck of the car. However, there are few study on the sensibility analysis of them. Most of all, the foot controller could be easily overlooked because it could be invisible. This study was based on relationship that the controllers fitted to the driving posture in the drivers' sensibility difference of two transmission modes, automatic and manual transmission. The results show the driver's preference driving posture and sensibility in two kinds of transmission cars. Consequently, it should be designed the seating buck for two different types respectively to be taken comfort driving posture and improve the safety for drivers. Also, it could reduce the fatigue and discomfort in the task of driving. The design of the controllers strongly effects on the drivers' response time. hereby this study was accessed to the sensibility of Korean with analyzing the relationship, quantitative data, and sensibility difference between two kinds of transmission cars.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.3 s.174
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• pp.567-580
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• 2000

This paper proposes an integrated approach, which is independent of specimen geometry and loading type, for predicting the fatigue life of spot welded specimens. We first establish finite element models reflecting the actual specimen behaviors observed on the experimental load-deflection curves of 4 types of single spot welded specimens. Using finite element models elaborately established, we then evaluate fracture parameter J-integral to describe the effects of specimen geometry and loading type on the fatigue life in a comprehensive manner. It is confirmed, however, that J-integral concept alone is insufficient to clearly explain the generalized relationship between load and fatigue life of spot welded specimens. On this ground, we introduce another effective parameter $J_e$ composed of $J_I$, $J_{II}$, $J_{III}$, which has been demonstrated here to more sharply define the relationship between load and fatigue life of 4 types of spot welded specimens. The crack surface displacement method is adopted for decomposition of J, and the mechanism of the mixed mode fracture is also discussed in detail as a motivation of using $J_e$.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.1
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• pp.137-144
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• 2013

This study analyzes structural analysis with fatigue and natural frequency on ATV knuckle. The maximum equivalent stresses are happened at the end of knuckle in case of model 1, 2 and 3. As these stresses are below the allowable stress, these models can be stable structurally. The fatigue damage possibility at model 1 becomes more than model 2 and 3. Model 2 or 3 has more durability than model 1 at fatigue. As the resonances are happened at the frequency more than 2000 Hz in case of model 1, 2 and 3, there is no resonance possibilities at real driving. Prevention against damage and durability prediction on automotive chassis parts can be effectively improved by applying this study result on knuckle and improving structural strength.

• Journal of Korean Society of Transportation
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• v.35 no.5
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• pp.423-433
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• 2017

During recent 5 years, it was recorded that 20% of total accident frequency and 30% of total number of death have been occurred due to drowsy driving. Drowsy driving accident is result from the loss of driving ability due to driver's accumulated fatigue. Continuous driving time can be measured as a surrogate variable to quantify the level of fatigue. The main purpose of this research is to investigate statistical correlation between the proportion of continuous driving vehicle (more than 2 hours) and the number of drowsy accidents. To carry this out, continuous driving time was measured using GPS route-guidance trajectory data. Also, accident frequency, traffic volume and segment length were collected to estimate safety performance function (SPF) for Jungbunearuk expressway in Korea. Through various types of estimated SPFs, statistical correlation was analyzed based on estimated statistical indices. This research can provide theoretical background for enforcement to regulate commercial vehicle driver's continuous driving time. In addition, throughout the trajectory data expansion, it is expected that strategy for anti-drowsy driving facilities installation can be established based on the suggested methodology.

• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.28-33
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• 2014

Recently, the actuator worked by the driving recovery-force of the thermo elastic martensitic transformation of shape memory alloys(SMA) has been studied. This paper presents a study on the fatigue life of shape memory alloy (SMA) actuators undergoing thermally induced martensitic phase transformation under various stress levels. shape memory recoverable stress and strain of Ti-44.5at.%Ni-8at.%Cu alloys were by means of constant temperature tensile tests. Differential scanning calorimetry (DSC) was employed in order to investigate the transformation characteristics of the alloy before the tests. the results were summarized as follows. The martensite inducing stress incerased with the increasing of the Cu-contents. The fatigue life decreased with the increasing of the test load and the Cu-content. The data acquired will be very useful during the design process of an SMA NiTiCu element as a functional part of an actuator.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.141-141
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• 2000

In the recent day, fatigue life prediction techniques play a major role in the design of components in th ground vehicle industry. Full scale durability testing in the laboratory is an essential of any fatigue life evaluation of components or structure of the automotive vehicle. Component testing is particularly important in today's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, multi-axis durability testing simulator is used to car교 out the fatigue test. In this paper, the operation software for simultaneously driving 3-axis simulator is developed and the real-time signals of input-output data are displayed in window of PC. Moreover, the displacements and the loads of 3-axis actuators are calibrated separately and the operating characteristics of the actuators are evaluated.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.143-151
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• 2001

In the recent day, fatigue life prediction techniques play a major role in the design of components in the ground vehicle industry. Full scale durability testing in the laboratory is an essential of any fatigue life evaluation of components or structure of the automotive vehicle. Component testing is particularly important in todey's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, Multi-axis durability testing device is used to carry out the fatigue test. In this paper, The operation software for simultaneously driving Multi-axis vibration testing device is developed and the input and output data are displayed in windows of PC controller with real time. Moteover the characteristics of the displacement and the load of Multi-axis actuators are calibrated separately.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1347-1353
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• 2011

Friction stir welding (FSW) method has extensively been used in manufacturing methods because of the several advantages over conventional welding methods, such as better mechanical properties, reduced occurrence of joining defects, high material saving, and low production time, etc. The aim of this paper is to review the optimal FSW conditions using the previous experimental results and is to investigate the fatigue crack growth rate in three different zones, WM, HAZ and BM for FSWed Al7075-T651 aluminum plates. As far as our experiments are concerned, the optimal conditions are obtained as rotation speed, 800rpm and travelling speed, 0.5mm/sec. The fatigue crack growth rate showed strong dependency on three different zones WM, HAZ and BM, and crack driving force.