• Journal of Biomedical Engineering Research
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• v.17 no.2
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• pp.221-226
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• 1996

Tendon reflex responses generated from mechanical stimulus had been studied for quantitative analysis of activity of tendon reflex, especially patellar tendon reflex responses are known to be a criterion for diagnosing the L3 or L4 radiculopathy. In this paper, we developed a digital signal processing system for analysis of the tendon reflex response. The system parameter, i.e., $\textit{sampling frequency, pre-amplification gain, input channel and filter bank}$ are selected by Using software switches. From the view points of flexibility, the system hardware is connected to an IBM PC for analyzing the tendon reflex parameters, amplitude, latency duration We applied the proposed system to the analysis of the patellar tendon reflex reponses. In the experiment, we measured latency, duration, amplitude of the reflex action potentials generated from vastus medialis, vastus lateralis and rectus femoris that compose quadriceps, and the measured data are analyzed througll the ANOVA test which has 5% significant level. As a result, we showed that the mean amplitude of reflex action potential at the vastus lateralis is larger than any other muscle and the mean latency of the reflex action potential at the rectus femoris is shorter than any other muscle.

• Journal of the Optical Society of Korea
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• v.13 no.4
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• pp.472-477
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• 2009

A Stokes polarimetry imaging (SPI) system was developed and utilized to detect tendon tears by constructing the degree of linear polarization (DOLP) image maps after linearly polarized light illumination. The micro and partial-thickness tears of turkey tendons were made and imaged by the SPI system at different incident polarization angles (IPA) with different mechanical loads on the tendon. The micro and partial-thickness tendon tears were detected by the DOLP images due to weak birefringence around the tears. The tendon tears were detected by a highest DOLP contrast at longest visible wavelength (Red, 650 ${\pm}$ 50 nm). All polarized images showed modulated DOLP as the incident polarization angle (IPA) was varied. The varying DOLP allowed the optimal detection of the micro and partial-thickness tendon tears at a certain IPA. The SPI system with variable IPA and spectral information can improve the detection of the tendon tears by higher visibility of fiber orientations, and thereby improve diagnosis and treatment of the tendon related injuries.

• The Journal of Korea Robotics Society
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• v.15 no.2
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• pp.190-196
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• 2020

Mechanical systems using tendon-driven actuators have been widely used for bionic robot arms because not only the tendon based actuating system enables the design of robot arm to be very efficient, but also the system is very similar to the mechanism of the human body's operation. The tendon-driven actuator, however, has a drawback caused by the friction force of the sheath. Controlling the system without considering the friction force between the sheath and the tendon could result in a failure to achieve the desired dynamic behaviors. In this study, a mathematical model was introduced to determine the friction force that is changed according to the geometrical pathway of the tendon-sheath, and the model parameters for the friction model were estimated by analyzing the data obtained from dedicated tests designed for evaluating the friction forces. Based on the results, it is possible to appropriately predict the friction force by using the information on the pathway of the tendon.

• Smart Structures and Systems
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• v.15 no.2
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• pp.375-393
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• 2015

In this study, local dynamic characteristics of mountable PZT interfaces are numerically analyzed to verify their feasibility on impedance monitoring of the prestress-loss in tendon anchorage subsystems. Firstly, a prestressed tendon-anchorage system with mountable PZT interfaces is described. Two types of mountable interfaces which are different in geometric and boundary conditions are designed for impedance monitoring in the tendon-anchorage subsystems. Secondly, laboratory experiments are performed to evaluate the impedance monitoring via the two mountable PZT interfaces placed on the tendon-anchorage under the variation of prestress forces. Impedance features such as frequency-shifts and root-mean-square-deviations are quantified for the two PZT interfaces. Finally, local dynamic characteristics of the two PZT interfaces are numerically analyzed to verify their performances on impedance monitoring at the tendon-anchorage system. For the two PZT interfaces, the relationships between structural parameters and local vibration responses are examined by modal sensitivity analyses.

• Journal of the Korean Society of Safety
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• v.29 no.1
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• pp.25-30
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• 2014

This paper deals with a numerical study on the deformation of a mono tendon anchor head. The anchor head is used to introduce the compression to concrete, and consists of wedges and a head. All kinematics, material and contact nonlinearity are included in the precise analysis of a mono tendon anchor head. A numerical study on a mono tendon anchor head is performed to investigate effects of friction and eccentricity of load by ABAQUS. From the numerical results, it is verified that the deformation of a mono tendon anchor head is affected by characteristics of materials, boundary condition between wedge and anchor head, eccentricity of load, etc.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.582-591
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• 2004

The purpose of this study was to determine the effects of elbow joint angle on mechanical properties, as represented by ultimate load, failure strain and elastic modulus, of bone-tendon specimens of common extensor tendon of the humeral epicondyle. Eight pairs of specimens were equally divided into two groups of 8 each, which selected arbitrarily from left or right side of each pair, positioned at 45$^{\circ}$ and 90$^{\circ}$ of elbow flexion and subjected to tension to failure in the physiological direction of the common extensor tendon. For comparison of the differences in the failure and elastic modulus between tendon and the bone-junction, data for both were evaluated individually. Significant reduction in ultimate load of bone-tendon specimens was shown to occur at 45$^{\circ}$. The values obtained from the bone-tendon junctions with regard to the failure strain were significant higher than those from tendon in both loading directions, but the largest failure strain at the bone-tendon junction was found at 45$^{\circ}$. The elastic modulus was found to decrease significantly at the bone-tendon junction when the loading direction switched from 90$^{\circ}$ to 45$^{\circ}$. Histological observation, after mechanical tensile tests, in both loading directions showed that failure occurred at the interface between tendon and uncalcified fibrocartilage in the thinnest fibrocartilage zone of the bone-tendon junction. We concluded that differences in measured mechanical properties are a consequence of varying the loading direction of the tendon across the bone-tendon specimen.

• Smart Structures and Systems
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• v.20 no.2
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• pp.181-195
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• 2017

In this study, the severity of damage in tendon anchorage caused by the loss of tendon forces is quantitatively identified by using the PZT interface-based impedance monitoring technique. Firstly, a 2-DOF impedance model is newly designed to represent coupled dynamic responses of PZT interface-host structure. Secondly, the 2-DOF impedance model is adopted for the tendon anchorage system. A prototype of PZT interface is designed for the impedance monitoring. Then impedance signatures are experimentally measured from a laboratory-scale tendon anchorage structure with various tendon forces. Finally, damage severities of the tendon anchorage induced by the variation of tendon forces are quantitatively identified from the phase-by-phase model updating process, from which the change in impedance signatures is correlated to the change in structural properties.

• Structural Engineering and Mechanics
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• v.28 no.5
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• pp.515-524
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• 2008

In this paper the effect of prestressing force on the first flexural natural frequency of beams is studied. Finite element technique is used to model the beam-tendon system, and the prestressing force is applied in the form of initial tension in the tendon. It is shown that the effect of prestressing force on the first natural frequency depends on bonded and unbonded nature of the tendon, and also on the eccentricity of tendon. For the beams with bonded tendon, the prestressing force does not have any appreciable effect on the first flexural natural frequency. However, for the beams with unbonded tendon, the first natural frequency significantly changes with the prestressing force and eccentricity of the tendon. If the eccentricity of tendon is small, then the first natural frequency decreases with the prestressing force and if the eccentricity is large, then the first flexural natural frequency increases with the prestressing force. Results of the present study clearly indicate that the first natural frequency can not be used as an easy indicator for detecting the loss of prestressing force, as has been attempted in some of the past studies.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.283-288
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• 2007

This paper presents an analytical prediction of Nonlinear characteristics of prestressed concrete bridges by strengthened of externally tendon considering the work sequence, using beam-column element based on flexibility method and tendon element. The beam-column element was developed with reinforced concrete material nonlinearities which are based on the smeared crack concept. The fiber hysteresis rule of beam-column element is derived from the uniaxial constitutive relations of concrete and reinforcing steel fibers. The tendon element represent the bonded tendon and unbonded tendon behaviors. Beam-column element and tendon element was be subroutine A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of RC and PSC structures was used. The proposed numerical method for prestressed concrete structures by strengthened of externally tendon is verified by comparison with reliable experimental results.

• Computers and Concrete
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• v.15 no.1
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• pp.55-71
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• 2015

This paper presents a novel harmony search (HS)-based data-driven single input rule modules (SIRMs)-connected fuzzy inference system (FIS) for the prediction of stress in externally prestressed tendon. The proposed method attempts to extract causal relationship of a system from an input-output pairs of data even without knowing the complete physical knowledge of the system. The monotonicity property is then exploited as an additional qualitative information to obtain a meaningful SIRMs-connected FIS model. This method is then validated using results from test data of the literature. Several parameters, such as initial tendon depth to beam ratio; deviators spacing to the initial tendon depth ratio; and distance of a concentrated load from the nearest support to the effective beam span are considered. A computer simulation for estimating the stress increase in externally prestressed tendon, ${\Delta}f_{ps}$, is then reported. The contributions of this paper is two folds; (i) it contributes towards a new monotonicity-preserving data-driven FIS model in fuzzy modeling and (ii) it provides a novel solution for estimating the ${\Delta}f_{ps}$ even without a complete physical knowledge of unbonded tendons.