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Fatigue property in gigacycle regime is focused as an important subject in recent years. In such a long-life region, a tremendous long period is required to perform the fatigue tests. In order to overcome this difficulty, special types of fatigue testing machines in rotating bending whose loading type is cantilever bending has been developed. It is known that this type of fatigue machine can be performed much quickly comparing with the tension and compression fatigue testing machines. And these experimental results are consistent with much data obtained by using traditional testing machines like tension and compression fatigue testing machines and the rotating bending fatigue test machines whose loading type is uniform bending named as Ono type, though it is unclear that much data of an ultrasonic fatigue testing machine are consistent with them. Although it prefers to perform the fatigue tests as fast as possible, but the maximum frequency of a rotating bending fatigue test are limited because of the possibility of temperature rise in specimen caused by the cyclic plastic work and the heat transfer from fatigue testing machine. Such local temperature rise might affect the fatigue property. However, the appropriate loading frequency limit is unclear because of the difficulty of the temperature measurement in the fracture portion of a specimen precisely during the rotating bending fatigue test. An in-situ temperature measuring technique is proposed to measure the temperature at the fracture portion of the specimen in real time during the fatigue testing, and the validity to determine the loading frequency of a rotating bending fatigue testing machine is discussed in this study.

本文データは学会の許諾に基づき J-stage から複製したものです。, The applications of REBaCuO superconducting bulks (RE: rare earth element or Y) have been investigated recently because of the enhancement of the superconducting characteristics such as critical current density Jc and the trapped field BT. A superconducting bulk can trap higher BT of over 17 T via conventional field-cooled magnetization (FCM) and BT=5.2 T via pulsed field magnetization (PFM), which has been intensively studied because a superconducting magnet is not used. This review article summarizes the magnetizing mechanism of the superconductors, the recent activities of PFM conducted experimentally and numerically, and the practical applications of several superconducting bulk magnet devices.

Application of Large scale lithium-ion battery to various satellites and space vehicles has progressed well because of high capacity and high specific energy demands. GS Yuasa Technology (GYT) had developed 100 Ah lithium ion cells in 1999. And we consecutively had developed 50 Ah and 175 Ah cell with the same basic electrode design as the 100 Ah cell. In this study, we investigated the internal cell temperature during charge and discharge operation that is important information to assess the cell life. The temperature measurements were performed on three sizes cells which are the 50 Ah, 100 Ah, and 175 Ah cell. Each cell were opened at the bottom of the cell case and four thermo couple temperature sensors were installed into the cell inside. The detail locations are top (in height)-center (of wound element), middle-center, bottom-center, and bottom-outer (of wound element, but inside of case). The opened cell bottom was sealed by epoxy resin for the charge and discharge test. And additional four thermo couple temperature sensors were attached at cell surface. The charge and discharge conditions are simulated LEO (Low Earth Orbit) and GEO (Geostationary Earth Orbit) satellite operation, as shown below. LEO: Charge: 0.5 CA for 60 minutes, Discharge: 0.8 CA for 30 minutes. GEO: Charge: 0.1 CA for 22 hours 48 minutes, Discharge: 0.58 CA for 72 minutes. These charge and discharge test were repeated six cycles at 0 C, 15 C, and 25 C, respectively. In these test, following results were obtained. Larger cell shows larger temperature difference within the cell. However, even at 175 Ah cell, the largest temperature difference was 3.3 C that is measured between inside and outside of wound element. As for top and bottom direction, the maximum temperature difference was 0.9 C. We think that the reason of this small temperature difference at vertical direction depends on high thermal conductivity of Cupper and Aluminum foil that consist the cell wound element., 資料番号: AA0063965002

Advanced Mission Research Center has been conducting studies on Space Solar Power Systems (SSPS) using microwave and laser beams for years organizing a special committee and working groups. In SSPS concepts and architectures study, system concepts and architectures of commercial type of microwave based SSPS (M-SSPS) and laser based SSPS (L-SSPS) has been studied for years. In this study, a major focus is on identifying system concepts, architectures and key technologies that may ultimately produce a practical and economical energy source. This paper presents the results of these study effort of JAXA and the most promising SSPS concepts, including their key technologies., 資料番号: AA0049500031, レポート番号: JAXA-SP-06-006

In this research and development, thermal design of TCS (thermal control system) of SDS-1 is conducted. This paper describes preliminary study on the thermal design. A thermal design policy is determined, based on environmental demands for TCS, and thermal instruments are arranged based on the thermal design policy. Thermal analyses were conducted and the validity of a thermal design was confirmed., 資料番号: AA0049500050, レポート番号: JAXA-SP-06-006

This report describes the development of a small-sized mechanical pump. The pump can be used in thermal control systems, such as Mechanical Pumped Loops (MPL) of spacecraft. This pump has following three features. (1) Ammonia used as working fluid. (2) Small sized design for spacecraft. (3) Axial type motor used for driving gear. The trochoid gear miniaturized the pump with the external diameter of 48 mm, the thickness of 19 mm and weight of 150 g. As a result of the performance test, 0.5 L/min flow rate, 45 kPa of total pressure and 2 MPa withstand pressure were achieved., 資料番号: AA0049054005, レポート番号: JAXA-SP-05-008

This paper presents a new method to evaluate the friction torque and the heat quantity generated in a spindle system. The decrease in the rotational speed of spindle during the free run period is precisely measured, and the angular deceleration is calculated. The heat quantity generated during the spindle rotation is evaluated as the product of the moment of inertia of spindle, the angular deceleration and the angular velocity. A device is newly developed to measure the rotational speed of spindle accurately for this purpose, which is basically composed of a photo interrupter attached to the spindle and a crystal oscillator of 2.5MHz clock pulse combined with a counter mounted on a personal computer board. The method was applied to evaluate the heat quantity generated in an air spindle, and it was proved that the heat quantity was accurately evaluated with a repeatability error of less than 1%. The heat quantity is obtained to increase by 4% due to an increase in the coefficient of viscosity of air which is caused by the increase in the air temperature.

The feed array for the 21 GHz band advanced broadcast test satellite has been studied in NHK and the preliminary study on the thermal rejection system for the array is executed in regard to loading the array to the satellite main truss body. This paper describes the examination result of the application of the flat type heat pipe to the thermal rejection system by the joint research with NHK., 資料番号: AA0049500049, レポート番号: JAXA-SP-06-006