A PSA framework for an Interim Dry Storage Facility Subjected to an Aircraft Crash Prof. Sanghoon LEE, Belal ALMOMANI, Dongchan JANG and Hyun Gook KANG (Keimyung University, Korea Advanced Institute of Science and Technology, Rensselaer Polytechnic Institute)
An overview of a risk evaluation framework for an aircraft crash into an interim spent fuel storage facility using a probabilistic safety assessment is presented. Damage evaluation of a detailed generic cask model in a simplified building structure under aircraft impact is discussed through a numerical structural analysis and an analytical fragility assessment. Sequences of the impact scenario are shown in a developed event tree, with uncertainties considered in the impact analysis and failure probabilities calculated. Risks are estimated for three specification levels of cask and storage facility structures to evaluate the influence of parameters relevant to design safety. The proposed assessment procedure includes the determination of loading parameters and reference impact scenario, structural response analyses of facility walls, cask containment, and fuel assemblies, and a radiological consequence analysis with dose-risk estimation. The risk results for the proposed scenario in this study are expected to be small relative to design basis accidents for best-estimated, conservative values. The importance of this framework is seen in the flexibility to evaluate facility capability to withstand aircraft impact and the expectation of potential realistic risks; the framework also provides insight into epistemic uncertainty in the available data, and into the sensitivity of design parameters for structural health management of interim dry storage facility.
Thermal Fatigue Analysis and Evaluation of Wheel-Rail Contact under Braking Conditions Ms. Soyoung LEE, Hailong SHAO, Dong-Hyung LEE, Ha-Young CHOI and Jongsoo LEE (Yonsei University, Korea Railroad Research Institute, Dongyang Mirae University)
Recently, reliability design considering the fatigue has been demanded for ensuring the driving safety for the high speed railway. In particular, the railway wheel and rail are subjected not only to mechanical load but also to high thermal load due to frictional heat generated when the railway wheel contacts with the brake shoe during tread braking. As repetitive thermal load accelerates damage to the wheel surface, it leads to shorten the replacement cycle and increase the maintenance cost. Therefore, we expect to achieve the economic efficiency by using the wheel over the life expectancy while maintaining the structural health. Initial braking velocity is one of the main factors affecting the behaviors of contact surface between the wheel and rail. Therefore, it is necessary to evaluate the effect of thermal stress according to it. In this study, through the thermal-mechanical analysis considering both mechanical load and thermal load caused frictional heat under braking conditions, thermal stress subjected to the contact surface between the railway wheel and rail was calculated. Based on these results, the thermal fatigue analysis was carried out to evaluate the safety under fatigue and predict the fatigue life.
Prediction of system reliability using failure types of components based on Weibull lifetime distribution Ms. Hee Yang KO, Si-Il SUNG and Yong Soo KIM (Kyonggi University, Inje Univ.)
Nowadays, products are complicated and standards of reliability are higher than ever before. In contrast, the time available for developing products has gradually decreased. In this context, assessment of the system reliability of products is an active field of study. In this paper, an experimental design was used to investigate the effect of the failure type of components on the whole system’s failure type. For this, a general procedure for estimating system reliability based on the Weibull distribution was adopted.
Experimental Study of the Vibration Fatigue for Beam with Hard Coating Damping Treatment Dr. Jingyu ZHAI, Hui CHEN, Yugang CHEN and Qingkai HAN (Dalian University of Technology)
The hard coating material, with its superior advantages to temperature and corrosion resistance, is an ideal material for controlling the vibration of structures duo to its high capacity to dissipate vibration energy. The hard coating material has been widely used in the aerospace field. In this paper, the vibration fatigue properties of plate with hard coating damping treatment are investigated further. An experiment is conducted to obtain the vibration fatigue mechanism of the hard coating plate, in which the vibration fatigue life of plate are measured under bending and local resonance condition. The vibration excitation is produced by the shaker driven by an amplified signal from vibration controller. Moreover, The influence of the vibration frequency, amplitude and various damping properties for the vibration fatigue life are all considered and compared. The results indicate that an appropriate selection hard coating parameters can obtain desirable damping properties and can improve the vibration fatigue life.