• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.45-48
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• 2007

The aim of this study is to estimate the compressive force of steel member using a system identification technique with vibration measurements. To date, several methods have been presented to estimate the compressive force using static and/or dynamic responses of the steel member. However, each and every one of these methods has its disadvantages as well as advantages in its procedures, level of accuracy, and equipment requirements. The paper reports a qualitative investigation of vibration under monoharmonic excitation. The methodology utilizes the relationship between the natural frequencies, the structural parameters, and the compressive force of the member. In this paper, experimental results are presented with a steel beam subjecting to several compressive forces and the proposed method is validated using both numerical and experimental data.

• Journal of the Korean GEO-environmental Society
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• v.20 no.4
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• pp.5-9
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• 2019

This paper is to provide the results of a pilot study of the usability and possibility of impact force response signal induced from impacting an object for the assessment of compressive strength of various materials (rock, concrete, wood, etc.) nondestructively. For this study, a device was devised for impacting an object and measuring the impact force. The impact was carried out by an initial rotating free falling impact and following repetitive impacts from the rebound action which eventually disappears. Wood and rock test specimens for different strengths were tested and an impact force response signal was measured for each test specimen. The total impact force signal energy which is assessed from integrating the impact force response signal was compared with the directly measured compressive strength for each specimen. The comparison showed that the total impact force signal energy has a direct relationship with the directly measured compressive strength and the results clearly indicated that the compressive strength of construction materials can be assessed nondestructively using total impact force signal energy which is assessed from integrating the impact force response signal induced from impacting an object.

• Journal of the Korean GEO-environmental Society
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• v.23 no.10
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• pp.13-19
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• 2022

This paper is to provide the results of usability of the impact force response signal induced from initial and successive rebound impacting a rock specimen for assessing the compressive strength of rock non-destructively. For this study, a device was devised for impacting a rock specimen and a system for measuring the impact force was set up. The impact was carried out by an initial rotating free falling impact and following repetitive impacts from the rebound action which eventually disappears. Three different kinds of rock specimen were tested and an impact force response signal was measured for each test specimen. The total impact force signal energy which is assessed from integrating the impact force response signal induced from initial and rebound impacts was compared with the directly measured compressive strength for each rock specimen. The comparison showed that the total impact force signal energy has a direct relationship with the directly measured compressive strength and the results clearly indicated that the compressive strength of rock can be assessed non-destructively using total impact force signal energy.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1690-1692
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• 2000

The principle of crimping connection is to produce a compressive connection force between terminal and cores(wire conductor). Compressive connection force is produced by pushing each other on that stress(crimping force) of barrel by restored elastic strain after plastic deformation and the expansion force of cores' elastic stress. And resistance and tension force between terminal and cores are determined according to the condition of compressive connection force. In this study, we've found out that the adaptive height which has maximum tensile force by measuring a tensile force with a height of terminal.

• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.335-343
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• 2011

Patellofemoral pain syndrome is the most common problem involving the knee, accounting for 25% of knee injuries. Repetitive, overuse activities cause increased force at the patellofemoral joint, resulting in pain during flexion and extension activities. Most research have been conducted in exploring the patellofemoral compressive force in gait, squat and lunges, even though in real cases, possibilities in landing exist. The purpose of this study was to compare the differences in patellofemoral compressive force according to two different height. Sixteen collegiate male students(age: 22.25 ${\pm}$ 3.30 yrs, height: 177.25 ${\pm}$ 4.44 cm, weight: 77.50 ${\pm}$ 8.18 kg) were chosen. The subjects performed drop landings in 45 cm, 60 cm. The findings demonstrated that higher height showed peak knee extension moment, quadriceps contraction force, patellofemoral compressive force with increased VGRF. Regarding the patellofemoral joint compressive force, it increased by quadriceps contraction force with knee flexion during landing, yet, it showed no difference in maximal knee flexion. To minimize patellofemoral joint stress and reduce the likelihood of developing PFPS, we recommend that predesigned quadriceps and hip muscle group strengthening are needed during conditioning and training.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.149-154
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• 2006

The cold expansion method (CEM) is one of the widely used a method to improve the fatigue behavior of materials in aerospace industry. Such improvement is due to the compressive residual stress developed when a tapered mandrel goes through the fastener holes a little smaller than the mandrel. CEM is retarded of crack initiation due to the compressive residual stress developed on the hole surface. Many researchers are studied a finite element analysis of residual stress around fastener hole. But in case of real model, fastener hole has a clamping force after CE. Therefore, it is respected that residual stress distributions should be changed due to clamping forces. In this paper, it was performed finite element analysis of residual stress by clamping force after CE in the plate having adjacent holes. From this study, it has been found that compressive residual stress near the hole increases according to clamping force. Also, the more increase clamping force, the more increases compressive residual stress. However, tensile residual stress increase beyond clamping force area.

• Structural Engineering and Mechanics
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• v.3 no.5
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• pp.475-495
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• 1995

In the past, physical models have been proposed, in compliance with the concept of the compressive-force path, for the realistic design of various statically determinate structural concrete members. The present work extends these models so as to encompass indeterminate RC structural forms. Pilot tests conducted on continuous beams and fixed-ended portal frames have revealed that designing such members to present-day concepts may lead to brittle types of failure. On the other hand, similar members designed on the basis of the proposed physical models attained very ductile failures. It appears that, unlike current design approaches, the compressive-force path concept is capable of identifying those areas where failure is most likely to be triggered, and ensures better load redistribution, thus improving ductility. The beneficial effect of proper detailing at the point of contraflexure in an indeterminate RC member is to be noted.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.391-398
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• 1998

The purpose of this study was to find the distribution and measurement of compressive and tensile stress when intrusi- on arch wire is forced engage with upper canine and to analysis stress at each section through FEM. And we compare compressive and tensile ratio at each section. The results were as follows. 1. At FA point and cemento-enamel junction of upper canine, compressive and tensile force ratio is about the same. 2. At apex, compressive force is the four times as tensile force. ; In intrusion, we show root resorption at apex. 3. At Cemento-enamel junction, the compressive and tensile force show the maximun value except FA Point.

• Safety and Health at Work
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• v.2 no.3
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• pp.236-242
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• 2011

Objectives: To determine the feasibility of predicting static and dynamic peak back-compressive forces based on (1) static back compressive force values at the lift origin and destination and (2) lifting speed. Methods: Ten male subjects performed symmetric mid-sagittal floor-to-shoulder, floor-to-waist, and waist-to-shoulder lifts at three different speeds (slow, medium, and fast), and with two different loads (light and heavy). Two-dimensional kinematics and kinetics were captured. Linear regression analyses were used to develop prediction equations, the amount of predictability, and significance for static and dynamic peak back-compressive forces based on a static origin and destination average (SODA) backcompressive force. Results: Static and dynamic peak back-compressive forces were highly predicted by the SODA, with R2 values ranging from 0.830 to 0.947. Slopes were significantly different between slow and fast lifting speeds (p < 0.05) for the dynamic peak prediction equations. The slope of the regression line for static prediction was significantly greater than one with a significant positive intercept value. Conclusion: SODA under-predict both static and dynamic peak back-compressive force values. Peak values are highly predictable and could be readily determined using back-compressive force assessments at the origin and destination of a lifting task. This could be valuable for enhancing job design and analysis in the workplace and for large-scale studies where a full analysis of each lifting task is not feasible.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2007.11a
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• pp.325-330
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• 2007

Uniaxial tensile test are generally much simpler than uniaxial compressive test. Uniaxial compressive test is experimentally more difficult because of the low buckling resistance of a sheet of paper. In order to avoid buckling, many researchers have applied various lateral restraint techniques to investigate paper uniaxial compression behavior. Adding unnecessary force to inhibit compressive deformation of the sheet is unwanted, but sufficient force must be used to inhibit buckling. This study has been carried out to develop new uniaxial compressive standard test method without exerting unnecessary force to paper specimen to prevent buckling.