• Journal of Mechanical Science and Technology
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• 제17권6호
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• pp.896-905
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• 2003

A linear motor has many advantages next to conventional feed mechanisms: high transitional speed and acceleration, high control performance, and good positioning accuracy at high speed. Through the omission of a power transfer element, the linear motor shows no wear and no backlash, has a long lifetime, and is easy to assemble. A disadvantage of the linear motor is low efficiency and resultant high-temperature rise in itself and neighboring structures during operation. This paper presents the thermal behavior of the linear motor as a feed mechanism in machine tools. To improve the thermal behavior, an insulation layer is used. By placing the insulation layer between the primary part and the machine table, both the temperature difference and the temperature fluctuation in the machine table due to a varying motor load are reduced.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.162-163
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• 2015

Thermal deformation behavior of high-strength concrete (HSC) exposed to fire is different from that of normal strength concrete (NSC). In case of ultra-high-strength concrete (UHSC), it is well known that thermal deformation behavior is greater than HSC. With increasing research of UHSC in buildings, it is necessary to understand the performance of UHSC at elevated temperatures considering loading condition. Therefore, evaluation on properties of thermal strain behavior properties of ultra high strength concrete by loading and high temperature was conducted.

• 한국정밀공학회지
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• 제19권6호
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• pp.184-191
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• 2002

This paper presents the thermal behavior of a synchronous linear motor with high speed and force. Such a linear motor can successfully replace ball lead screw in machine tools because it has a high velocity, acceleration and good positioning accuracy. On the other hand, low efficiency and high heating up during operation are disadvantage of linear motors. For the application of linear motors to machine tools a water-cooling system is often used. In this research, structure of the linear motor and water cooler is changed to improve the thermal behavior of the linear motor. Some important effects of an integrated cooler, an U-cooler and a thermally symmetrical cooler are presented.

• 한국정밀공학회지
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• 제19권7호
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• pp.163-170
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• 2002

This paper presents some measures far the optimization of the thermal behavior of linear motors, which are used as a high speed feed mechanism in machine tools. Thermo-Sandwich-Construction using two cooling circuits and an insulation layer shows an effective cooling system for linear motors. Conducting sheet can be also used to reduce heat flow from linear motor to machine table. Cooling pipe is a simple and effective cooling system for the secondary part of synchronous linear motor. Through the combination of the Thermo-Sandwich-Construction, conducting sheet and cooling pipe the thermally optimized linear motor shows a well improved thermal behavior in comparison with the prototype motor.

• 한국정밀공학회지
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• 제28권4호
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• pp.505-512
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• 2011

Linear permanent magnet synchronous motors utilize high-energy product permanent magnet to produce high thrust, velocity and acceleration. Such motors are finding applications requiring high positioning accuracy and speed response, for example, machine tools, in the absence of mechanical gears and ball screw systems. A disadvantage of the linear motors is high power loss in comparison with rotary motors. For the application of the linear motors to machine tools, it is required to use water coolers and to improve the thermal behavior through insulation and structure optimization or control strategies. This paper presents the function of the secondary part of the linear synchronous motor as to the thermal behavior and the improving method. The result shows cooling pipe combined with an insulation layer is a suitable design for improving of the thermal behavior.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.80-81
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• 2015

Thermal deformation behavior of high-strength concrete (HSC) exposed to fire is different from that of normal strength concrete (NSC). In case of ultra-high-strength concrete (UHSC), it is well known that thermal deformation behavior is greater than HSC. With increasing research of UHSC in buildings, it is necessary to understand the performance of UHSC at elevated temperatures considering loading condition. Therefore, evaluation on properties of thermal strain behavior properties of ultra high strength concrete by loading and high temperature was conducted.

• 한국정밀공학회지
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• 제14권2호
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• pp.33-40
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• 1997

Recently, there are an increasing needs for high speed rotating spindle which is an important mechanical ele- ment for a high efficiency machine tool in order to shorten machining time and cut production costs. The heat gen- eration is the most important problem in the motor integrated spindle. In this study, the effects of temperature distribution and thermal behavior according to the oil-air lubrication and cooling conditions are investigate theo- retically and experimentally on the motor-integrated spindle under unloading condition. The experimental spin- dle system is composed with the angular contact steel ball bearings, oil-air lubrication, air or oil jacket cooling system. To analyze the thermal behavior and cooling characteristics for the motor integrated spindle, the analysis using the finite element method is carried out. The analytical results are compared with the experimental results.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.728-744
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• 2024

The presence of hydrogen absorbed by zirconium-based cladding materials during reactor operation can trigger degradation mechanisms and endanger the rod integrity. Ensuring the durability of the rods in extended time-frames like dry storage requires anticipating hydrogen behavior using numerical modeling. In this context, the present paper describes a hydrogen post-processing tool for Falcon - HYPE, a PSI's in-house tool able to calculate hydrogen uptake, transport, thermochemistry, reorientation of hydrides and hydrogen-related failure criteria. The tool extracts all necessary data from a Falcon output file; therefore, it can be considered loosely coupled to Falcon. HYPE has been successfully validated against experimental data and applied to reactor operation and interim storage scenarios to present its capabilities.

• Advances in Computational Design
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• 제2권2호
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• pp.107-119
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• 2017

The Micro circular diaphragm (MCD) is the mechanical actuator part used in the micro electro-mechanical sensors (MEMS) that combine electrical and mechanical components. These actuators are working under harsh mechanical and thermal conditions, so it is very important to study the mechanical and thermal behaviors of these actuators, in order to do with its function successfully. The objective of this paper is to determine the thermo-mechanical behavior of MCD by developing the traditional bulge test technique to achieve the aims of this work. The specimen is first pre-stressed to ensure that is no initial deflection before applied the loads on diaphragm and then clamped between two plates, a differential pressure (P) and temperature ($T_b$) is leading to a deformation of the MCD. Analytical formulation of developed bulge test technique for MCD thermo-mechanical characterization was established with taking in-to account effect of the residual strength from pre-stressed loading. These makes the plane-strain bulge test ideal for studying the mechanical and thermal behavior of diaphragm in both the elastic and plastic regimes. The differential specimen thickness due to bulge effect to describe the mechanical behavior, and the temperature effect on the MCD material properties to study the thermal behavior under deformation were discussed. A finite element model (FEM) can be extended to apply for investigating the reliability of the proposed bulge test of MCD and compare between the FEM results and another one from analytical calculus. The results show that, the good convergence between the finite element model and analytical model.

• Fibers and Polymers
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• 제5권1호
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• pp.31-38
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• 2004

In the present paper, a variety of fiber reinforcements, for instance, stabilized OXI-PAN fibers, quasi-carbon fibers, commercial carbon fibers, and their woven fabric forms, have been utilized to fabricate pseudo-unidirectional (pseudo-UD) and 2-directional (2D) phenolic matrix composites using a compression molding method. Prior to fabricating quasi-carbon fiber/phenolic (QC/P) composites, stabilized OXI-PAN fibers and fabrics were heat-treated under low temperature carbonization processes to prepare quasi-carbon fibers and fabrics. The thermal conductivity and thermal expansion/contraction behavior of QC/P composites have been investigated and compared with those of carbon fiber/phenolic (C/P) and stabilized fiber/phenolic composites. Also, the chemical compositions of the fibers used have been characterized. The results suggest that use of proper quasi-carbonization process may control effectively not only the chemical compositions of resulting quasi-carbon fibers but also the thermal conductivity and thermal expansion behavior of quasi-carbon fibers/phenolic composites in the intermediate range between stabilized PAN fiber- and carbon fiber-reinforced phenolic composites.