• International Journal of Aeronautical and Space Sciences
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• v.18 no.1
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• pp.63-69
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• 2017

In this paper, composite laminate pull-through resistance was analyzed using the FEM method and compared with test results. 2D and 3D simplified FEM models, a nonlinear analysis, and a progressive failure analysis utilizing three composite laminate failure theories Maximum Stress, Maximum Strain, and Tsai-Wu were used to predict the FEM results with the test results. The load and boundary conditions of the test were applied to the FEM to simulate the test. A composite laminate pull-through test (ASTM D7332 Proc. B) was designed with a special fixture to collect more precise data. The test results were compared with the FEM analysis results.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.334-336
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• 1998

This paper deals with the problem of the magnetizing yoke fixture. The experimental test has been performed using the yoke fixture made of bakelite as well as ferromagnetic. The magnetizing current is the most essential criterial factor for delivering the impulse energy to the magnetized material, i.e ferrite core. The yoke of nonferromagnetic has shown its better performance in experimental results as well as in the finite element analysis.

• The Journal of the Korean dental association
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• v.53 no.5
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• pp.360-367
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• 2015

Purpose : The purpose of this study was to evaluate the effect of amount of cantilever in intra-crown according to implant fixture position on mechanical strength of internal conical joint type implant. Materials and Methods : Internal conical joint type implant fixture, abutment screw, abutment was connected and gold alloy prostheses were fabricated and cemented on abutment. For fatigue fracture test, the specimens were loaded to the 350 N, 2,000,000 cycle on 3, 4, 5, and 6 mm off-center of gold alloy prostheses. The fracture pattern of implant component was observed. Results : No fatigue fracture found on 3 and 4 mm group. But initial crack pattern found on 3 specimens of 4 mm group. Fatigue fracture found on all specimens of 5 mm group. But complete fracture was not observed. One specimen of 6 mm group fracture completely. Implant fixture fracture wax not observed. Conclusion : The mechanical failure of implant prostheses increased with the loading area farther from center of implant fixture. To reduce mechanical problem of internal joint type implant, surgical and prosthetic consideration is needed.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.4
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• pp.552-560
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• 2000

Purpose : The purpose of this study was to determine proper position and angulation of an implant for immediate implantation. Materials and Method : From the years 1997 to 2000. 52 Denta $scan^R$ views, 22 upper and 32 lower jaw with an average age of 43 and 40 respectively, were investigated, which comprise intact upper and lower 6 anterior teeth and premolars. On the Denta $scan^R$, the optimal placement for the immediated implantation was simulated. The measuring methods included 1) Angulation difference between tooth long axis and alveolar bone process. 2) Angulation difference of long axis between tooth and installing fixture 3) Distance between center of tooth at cervical area and center of fixture. 4) Distance from root apex to the bone limit of vital structure. One sample t-test was used for statistical analysis. Result : The results were as follows. 1) At the maxillary central incisor and lateral incisor, angulation difference of long axis between tooth and installing fixture was respectively 0.5 and 3.2 degrees with the fixture center's palatally positioned 2mm apart from tooth center. 2) At the lower anterior 6 teeth, that was about $-2.8^{\circ}\;to\;-4.6^{\circ}$ with the fixture center's lingually positioned 1mm apart from tooth center. 3) At the maxillary canine and premolar, that was respectively $11.8^{\circ}\;and \;7.2^{\circ}$ with the fixture center palatally positioned $2\sim2.4mm$ apart from tooth center. 4) At the lower premolar area, that was about $0^{\circ}\;to\;2^{\circ}$ with the fixture center's lingually positioned $0.5{\sim}1mm$ apart from tooth center. 5) Distance from root apex to the bone limit of vital structure, at the maxillary anterior and premolars. was the range of 10 to 12mm, and at the mandibular anterior teeth and the 1st premolar, that was the range of 18 to 20mm. Conclusion : The proper implant position of maxillary anterior and premolar teeth is as paralleled as or more buccally angulated than long axis of tooth with the fixture center's palatally positioned. In mandiblular anterior region, long axis of implants is lingully angulated compared with long axis of tooth and in premolar, almost parelleled with long axis of tooth and alveolar process.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.370-378
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• 2016

Purpose: The purpose of this study was to investigate screw joint stability and sagittal fit between internal connection implant fixtures of two different manufacturers and customized abutments. Materials and methods: Internal connection implant systems from two different manufacturers (Biomet 3i system, Astra Tech system) were selected for this study (n=24 for each implant system, total n=48). For 3i implant system, half of the implants were connected with Ti ready-made abutments and the other half implants were connected with Ti CAD-CAM custom ones of domestic-make (Myplant, Raphabio Co., Seoul, Korea) and were classified into Group 1 and Group 2 respectively. Astra implants were divided into Group 3 and Group 4 in the same way. Micro-CT sagittal imaging was performed for fit analysis of interfaces and preloading reverse torque values (RTV) were measured. Results: In the contact length of fixture-abutment interface, there were no significant differences not only between Group 1 and Group 2 but also between Group 3 and Group 4 (Mann-Whitney test, P>.05). However, Group 2 and Group 4 showed higher contact length significantly than Group 1 and Group 3 in abutment-screw interface as well as fixture-screw one (Mann-Whitney test, P<.05). In addition, RTV was lower in CAD-CAM custom abutments compared to ready-made ones (Student t-test, P<.05). Conclusion: It is considered that domestically manufactured CAD-CAM custom abutments have similar fit at the fixture abutment interface and it could be used clinically. However, RTV of CAD-CAM custom abutments should be improved for the increase of clinical application.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.3
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• pp.269-281
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• 2008

Fatigue or overload can result in mechanical problems of implant components. The mechanical strength in the implant system is dependent on several factors, such as screw and fixture diameters, material, and design of the fixture-abutment connection and abutment. In these factors, the last rules the strength and stability of the fixture-abutment assembly. There have been some previous reports on the mechanical strength of the fixture-abutment assembly with the compressive bending test or short-term cyclic loading test. However, it is restrictive to predict the long-term stability of the implant system with them. The purpose of this study was to evaluate the influence of the design of the fixture-abutment connection and abutment on the mechanical strength and failure mode by conducting the endurance limit test as well as the compressive bending strength test. Tests were performed according to a specified test(ISO/FDIS 14801) in 4 fixture-abutment assemblies of the Osstem implant system: an external butt joint with Cemented abutment (group BJT), an external butt joint with Safe abutment (group BJS), an internal conical joint with Solid abutment (group CJO), and an internal conical joint with ComOcta abutment (group CJT). The following conclusions were drawn within the limitation of this study. Compressive bending strengths were decreased in order of group BJS(1392.0N), group CJO(1261.8N), group BJT(1153.2N), and group CJT(1110.2N). There were no significant differences in compressive bending strengths between group BJT and group CJT(P>.05). Endurance limits were decreased in order of group CJO(600N), group CJT(453N), group BJS(360N), and group BJT(300N). 3. Compressive bending strengths were influenced by the connection and abutment design of the implant system, however endurance limits were affected more considerably by the connection design.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.366-370
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• 2003

This paper introduces a new design and fabrication technology of 28 GHz low-cost up and down converter modules for digital microwave radios, The design of the converter module is based on unit circuit blocks, which are to be characterized using a special test fixture. Based on the cascade analysis of the module the 28 GHz up and down converter modules have been designed and implemented. The measured module performance agrees with the cascade analysis. New components such as a tapped edge-coupled filter and a new Ka-band waveguide-to-microstrip transition, which are less sensitive to fabrication tolerances, have been used in the module implementation.

• Coupled systems mechanics
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• v.12 no.5
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• pp.445-459
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• 2023

In this study, a cyclic tensile test on a notched butterfly specimen made of woven glass fiber composite was performed on a modified Arcan fixture. During the mechanical test, the sample was monitored with a hybrid stereoscopic system comprised of two visible lights and one infrared camera. The visible light cameras were employed for kinematic measurements using a finite-element-based multiview correlation technique. A semi-hybrid correlation approach was followed, providing Lagrangian temperature fields of the Region of Interest. Due to the complex composite architecture and specimen shape, localized shearing was observed during the tensile loading. Furthermore, asymmetrical damage developed around the notches as revealed by localized strains and thermal hot spots.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.671-672
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• 2012

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.3
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• pp.10-16
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• 1991

The error networks due to the measuring systems and the test fixture must be previously calibrated in order to characterize the microwave devices. In this paper, it is presented a new method to characterize the error networks in which only two different microstrip lines are used for the calibration. Once each length of two calibrat- ing microstrip lines is accurately defined, the calibrated data can be easily obtained without acknowledgement for the propagation constant. The end effect is not considered when fabricated the microstrip lines used to calibration. The ATF13736 GaAs MESFET is characterized by means of the calibrating procedure with this method. The range of measuring frequency is 2 to 18 GHz, and the bias voltage and current are $V_{DS}$ =2.5V, $I_{DS}$ =20mA, respectively. Compared the calibrated data with data sheet, it is showed that the magnitude is nearly agreed with each other and the phase is deviated by 0.1 to 12 degrees in lower frequencies.