The failure behaviours of unidirectional pultruded carbon fiber reinforced polymer (CFRP) composites were monitored by the electrical resistance measurement during tensile loading, three-point-bending, interlaminar shear loading. The tensile failure behaviour of carbon fiber tows was also investigated by the electrical resistance measurement. Infrared thermography non-destructive evaluation was performed in real time during tensile test of CFRP composites to validate the change of microdamage in the materials. Experiment results demonstrated that the CFRP composites and carbon fiber tows were damaged by different damage mechinsms during tensile loading, for the CFRP composites, mainly being in the forms of matrix damage and the debonding between matrix and fibers, while for the carbon fiber tows, mainly being in the forms of fiber fracture. The correlation between the infrared thermographs and the change in the electrical resistance could be regarded as an evidence of the damage mechanisms of the CFRP composites. During three-point-bending loading, the main damage forms were the simultaneity fracture of matrix and fibers firstly, then matrix cracking and the debonding between matrix and fiber were carried out. This results can be shown in Fig. 9(a) and (b). During interlaminar shear loading, the change in the electrical resistance was related to the damage degree of interlaminar structure. Electrical resistance measurement was more sensitive to the damage behaviour of the CFRP composites than the stress/time curve.

This paper is intended to compare between the Bayesian estimate of a failure rate and the failure rate of a mixed distribution. For the sake of simplification, an exponential distribution and a gamma distribution are adopted as a sampling distribution and its natural conjugate prior distribution. The result shows that both the failure rates are being updated using data and they differ in whether they are functions of unobserved future data or not.

본 논문에서는 일축인장하중을 받고 있는 8-매 주자직 복합재료의 적층 위상변화가 등가물성치 및 응력분포에 미치는 영향을 연구하였다. 등가물성치 및 응력은 임의의 배열을 갖는 적층 구조물에 대한 단위구조 해석을 통해 계산하였으며, 마크로요소를 사용하여 효율적인 계산을 수행하였다. 계산 결과, 섬유다발 미세구조의 변화는 응력분포에 큰 영향을 미치는 것으로 나타났다. 섬유다발 및 수지에서의 응력은 섬유다발의 이동에 따라 서로 다른 분포를 보였고, 수지영역에서의 최대응력은 매우 넓은 범위에 걸쳐 분포하였다.

본고에서는 국제합작투자 이론적 배경으로서 시장실패와 조직실패 위험의 상쇄(trade-off) 메카니즘에 대한 분석이 이루어졌다. 시장실패란 거래비용에 의한 정상시장거래(arms-length transaction) 실패를 나타내며 조직실패란 관료비용(bureaucratic costs)에 의한 내부화의 실패를 의미한다. 해외진입 방식으로서 라이선싱은 정상시장거래 형태이며 단독투자는 완전 내부화, 그리고 합작투자는 준내부화(quasi-internalization)의 형태로 볼 수 있다. 과거의 연구들에 있어서는 시장실패에 의한 거래비용이론에 기초하여 이들 거래통제구조, 즉 해외진입방식의 선택에 대한 연구가 주를 이루었다. 즉 시장실패 위험이 높을수록 정상시장거래 보다는 내부화 형태를 선호한다는 것이다. 그러나 시장실패 위험만 가지고서는 합작투자 당위성과 그 소유구조를 충분히 설명할 수 없다. 기업은 해외진입방식 선택시 시장실패뿐만 아니라 조직실패 위험도 고려할 것이다. 시장실패 시와는 달리 조직실패 위험이 높을 경우에는 기업은 내부화 수준을 낮추거나 정상시장거래 방식을 선호할 것이다. 문제는 시장실패와 조직실패 위험이 모두 높거나 낮을 경우에 기업이 취할 수 있는 대안이다. 이를테면 높은 시장실패는 기업으로 하여금 단독투자를 선호케 하나 반대로 조직실패 가능성은 시장거래방식으로서 라이선싱을 선호케하는 상황에 빠지게 한다. 시장실패와 조직실패 위험이 모두 낮을 경우에도 마찬가지이다. 따라서 기업은 시장실패와 조직실패가 모두 높거나 낮은 상황 하에서는 이 두 극단적인 대안 중 어느 하나의 대안을 고수하기보다는 양극단의 절충을 꾀하고자 할 것이다. 즉 거래비용과 내부조직비용을 어느 정도 통제하고 상쇄시킬 수 있는 합작투자가 합리적인 대안이 된다는 것이다. 요컨대 기업간 합작을 통해 한편으로는 시장거래에서 발생되는 거래비용을 어느 정도 낮출 수 있고 또 다른 한편으로는 내부조직비용도 반감시킬 수 있는 것이다.

This paper is to develop replacement models under minimal repair with exponential polynomial wavelet failure rate function. Wavelets have good time-frequency localization, fast algorithms and parsimonious representation. Also this study is presented along with numerical examples using sensitivity analysis for exponential polynomial trigonometric failure rate function.

Reliability calculation of a system is frequently required in industrial, military, and everyday life situations. For such a calculation, it is necessary to specify the configuration of components and subsystems, the failure mode of each component, and the states in which the system is classified as failed. In this paper, we are primary interested in the time to the first failure of a system. And we discuss failure probability of coherent system under various condition, especially focus on probability calculation of subsystem failure before system failure used by Bayes formula. Problem statement and general applications illustrated by several examples.

Today, facilities are composed of many complex components or parts. Because of this characteristics, the frequency of failures is decreasing, but the strength of failures is increasing; therefore, the failure analysis about many complex components or parts was needed. In the former research about Fault Tree Analysis, failure data of similar facilities have been used for forecasting about target system or components, but in case that the system or components for forecasting failure is new or qualitative and quantitative data are given simultaneously, there are many difficulty in using Fault Tree Analysis with this incorrect failure data. Therefore, this paper deal with the Fault Tree Analysis method which be applied with Fuzzy theory in above case. In case that , therefore, if there is no the correct failure data, it is represented a system or components as qualitative variable. subsequently, it converted to the quantitative value using fuzzy theory, and the values used as the value for failure forecast.

Circuitry to be connected to a Telecommunication Network consists of SELV CIRCUITS or TNV CIRCUITS. So International Standards, like as ITU-T Recommendation K.11, UL 1950, CSA C22.2 950 have been taken to reduce the risk that the Overvoltages from the power lines and from electrictraction lines, that may be received from the telecommunication network. Legal requirements may exist regarding permission to connect equipment having PTC components to a telecommunication network. Surge suppressors that bridge the insulation shall have a minimum d.c. sparkover voltage of 1.6 times the rated voltage or 1.6 times the upper voltage of the tared voltage range of the equipment. If left in place during electric strength testing of insulation, they shall not be damaged. In this work, The Conception ＆ Fail-Mode Analysis of PTC components for Over-Current Protection is proposed. It guarantees the protection for PL Claim about this Subject.

P/M high speed steels(1.28% C, 4.20% Cr, 6.40% W, 5.00% Mo, 3.10% V, bal. Fe) from two different venders were applied to powder compacting punch. The test results show that failure lifes were very different between two punches. These were no difference in volume fraction and mean size of carbides(MC or M6C) but non-metallic inclusions in two punches. Small amount of non-metallic inclusion in the punch did not greatly affect impact energy and transverse rupture strength (TRS). But, fatigue life was drastically decreased by non-metallic inclusions. These results show that fatigue failure was initated around non-metallic inclusion by cyclic load and the fatigue life was greatly affected by the presence of non-metallic inclusions in the punch.

캘리포니아의 강구조 모멘트프레임은 1994년 노스리지 지진시 6.8의 규모와 진앙지에서 근접한 지리적인 악조건에도 불구하고 붕괴나 인명피해 없이 잘 견뎌냈다. 그러나 이후 시행된 조사에서 경제적으로 지진시 안전하다고 믿어져 널리 쓰인 welded flange-bolted web(WFBW) 강접합부(moment connection)의 기둥과 용접의 경계면에서 취성 파괴가 다수 발견되었다. 이논문은 선형파괴역학과 노스리지진이후의 WFBW 강접합부 실험을 이용하여 WFBW 강접합부와 노스리지지진이후 기존 강접합부의 대안으로 추천되고 있는 reduced beam section (RBS) 강접합부의 취성 파괴강도를 결정하는 수치적인 방법을 제안하고 이를 이용하여 이들 강접합부의 취성 파괴모드를 추정하였다.