Jeong Ho Kim

Bio: Jeong Ho Kim is an academic researcher from Inha University. The author has contributed to research in topics: Materials science & Hypersonic speed. The author has an hindex of 5, co-authored 16 publications receiving 83 citations. Previous affiliations of Jeong Ho Kim include UPRRP College of Natural Sciences.

Hard-landing Simulation by a Hierarchical Aircraft Landing Model and an Extended Inertia Relief Technique

Abstract: In this work, an efficient aircraft landing simulation strategy is proposed to develop an efficient and reliable hard-landing monitoring procedure. Landing stage is the most dangerous moment during operation cycle of aircraft and it may cause structural damage when hard-landing occurs. Therefore, the occurrence of hard-landing should be reported accurately to guarantee the structural integrity of aircraft. In order to accurately determine whether hard-landing occurs or not from given landing conditions, full nonlinear structural dynamic simulation can be performed, but this approach is highly timeconsuming. Thus, a more efficient approach for aircraft landing simulation which uses a hierarchical aircraft landing model and an extended inertia relief technique is proposed. The proposed aircraft landing model is composed of a multi-body dynamics model equipped with landing gear and tire models to extract the impact force and inertia force at touch-down and a linear dynamic structural model with an extended inertia relief method to analyze the structural response subject to the prescribed rigid body motion and the forces extracted from the multi-body dynamics model. The numerical examples show the efficiency and practical advantages of the proposed landing model as an essential component of aircraft hard-landing monitoring procedure.

Prediction of Pyroshock-Reduced Separation Nut Behaviors

Abstract: In this work, an efficient model is proposed to predict the complicated coupling behavior of a pyroshock-reduced separation nut, which has two variable-volume chambers connected by the vent hole. T...

Efficient Prediction of the Temperature History of a Hypersonic Vehicle Throughout the Mission Trajectory with an Aerodynamic Thermal Load Element

Abstract: This work introduces an efficient approach for aero-thermo-mechanical analysis to predict the temperature history of a hypersonic vehicle during its full mission trajectory. The approach uses a recently proposed aerodynamic thermal load element, in which the effects of aerodynamic pressure and aerodynamic heating are efficiently considered using local piston theory and the Eckert reference temperature method, respectively. This element is implemented as a user-subroutine in commercial software to handle realistic models for the aero-thermo-mechanical analysis, such as the X-43A. A finite element model of the X-43A is constructed for a benchmark test. Using the model, an aero-thermo-mechanical analysis is carried out while considering the full mission trajectory of the X-43A. The predicted temperature results are compared with recorded flight test data from the X-43A. Additionally, the aero-thermo-mechanical behavior of the hypersonic vehicle is investigated according to various parameters. The investigation confirms that the approach can be efficiently used in the design of hypersonic vehicles with considerable savings in computational cost.

An Introduction to the Design and Behavior of Bolted Joints

Abstract: Although the title of this book includes the word “introduction”, the treatment of the subject is extensive and complete. The material goes well beyond the coverage of bolted joint design received in a typical undergraduate machine design course. The easy-to-read text begins with the fundamentals of bolt strength, deformation, and material selection and proceeds to cover the topics of preload, torque, and stretch control. The emphasis is on practical considerations for the efficient design of joints, including cost, ease of assembly, inspection, and disassembly. This second, revised edition has expanded the coverage of corrosion, fatigue, gaskets, and ultrasonic measurement of bolt strain. Also included are discussions of the failure modes and mechanisms of bolted joints. Case histories from industry are presented throughout the text to illustrate key points. Many up-to-date references are presented at the end of each chapter to allow the reader to pursue individual topics further, if desired. The text contains several appendices with useful tables and formulas for quick reference. The author has broad experience in the subject area from many years as a consultant to the power generation and nuclear industry, active participation on society working groups such as ASME and PVRC, as well as the presentation of numerous seminars on the topic. This book would serve as a valuable desk reference for engineers concerned with the design and performance of bolted joints.

Efficacy and Interaction of Antioxidant Supplements as Adjuvant Therapy in Cancer Treatment: A Systematic Review

Abstract: Oxidative stress is a key component in carcinogenesis. Although radiation produces reactive oxygen species, some anticancer agents such as alkylating agents, platinum and antitumor antibiotics exert cytotoxicity by generating free radicals. Nonenzymatic exogenous antioxidants such as vitamins, minerals, and polyphenols can quench ROS activity. However, whether antioxidants alter antitumor effects during radiotherapy and some types of chemotherapy remains unclear. In the present study, we reviewed antioxidants as an adjuvant therapy for cancer patients during chemotherapy or radiotherapy. Electronic literature searches were performed to select all randomized controlled clinical trials (RCTs) in which antioxidants were administered to cancer patients along with chemotherapy or radiotherapy. Articles or abstracts written in English were included. In total, 399 reports received primary screening. Duplicated articles and those meeting the exclusion criteria (not RCT, not human, and no oral administration) were excluded. Finally, 49 reports matching the inclusion criteria were included. It was difficult to determine whether antioxidants affect treatment outcomes or whether antioxidants ameliorate adverse effects induced by chemotherapy and radiotherapy. It is desirable to use an evidence-based method to select supplements best suited to cancer patients. Although there are many opinions about risks or benefits of antioxidant supplementation, we could mostly conclude that the harm caused by antioxidant supplementation remains unclear for patients during cancer therapy, except for smokers undergoing radiotherapy.