• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.519-530
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• 1998

In this paper, the basic study on the design of the flexible keel of the energy-storage prosthetic foot was performed in order to Improve the walking performance and Increase the activities of the below knee amputees. Based on the analysis of the anthropometric data and the normal gait on two dimensional sagittal plane available In the literature, we presented a model of the basic structure of the flexible keel of the prosthetic foot. The model of the basic structure was composed of the simple beams, and linear rotational spring and damper. Laminated carbon fiber-reinforced composites were selected as the material of the basic structure model of the flexible keel In order to apply the high strength and light weight materials to the basic structure of the flexible keel of the prosthetic foot. The recoverable strain energy In response to the change of beam shape was calculated bur the finite element analysis and it was suggested that the change of beam shape could be the design variable in flexible keel design. The simulation process was systematically designed by using orthogonal array table in order to design the flexible keel structure which could store the more recoverable strain energy. finite element analysis was carried but according to the design of simulations by using the finite element program ABAQUS and the flexible keel structure of the energy-storage prosthetic foot was obtained from the analysis of variance(ANOVA). The dynamic simulation model of the prosthetic walking using the flexible keel structure was made and the dynamic analysis was carried but during one walk cycle. Based on the above results, an effective design process was presented for the development of the prosthetic fool system.

• Journal of Yeungnam Medical Science
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• v.20 no.2
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• pp.160-168
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• 2003

Background: Confirm the stability of intervertebral disc sustaining each fused lumbar spine cases, comparing vertical compression, A-P shear force and rotational moment on intervertebral disc of instrumented lumbar spine with simple vertical compression load and follower load using finite element analysis. Materials and Methods: We analyze the stability of intervertebral disc L4-5 supporting fused lumbar spine segments. After performing finite element modelling about L1-L5 lumbar vertebral column and L1-L4 each fusion level pedicle screw system for fused lumbar spine fine element model. Intervertebral discs with complex structure and mechanical properties was modeled using spring element that compensate stiffness and tube-to-tube contact element was employed to give follower load. Performing geometrical non-linear analysis. Results: The differences of intervertebral disc L4-5 behavior under the follower compression load in comparision with vertical compression load are as follows. Conclusion: As a result of finite element interpretation of instrumented lumbar spine, the stability of L4-5 sustaining fused lumbar segment, the long level fused lumbar spine observed hing stability under follower load. This research method can be the basis tool of effects prediction for instrumentation, a invention of a more precious finite element interpretation model which consider the role of muscle around the spine is loaded.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.4 s.316
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• pp.42-47
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• 2007

To reduce the chattering errors of reed switch sensors in the automatic remote measurement of water meter a reed switch sensor was analyzed and improved. The operation of reed switch sensors can be described as a mechanical contact switch by approximation of permanent magnet piece to generate an electrical pulse. The reed switch sensors are used mostly in measurement application to detect the rotational or translational displacement. To apply for water flow measurement devices, the reed switch sensors should keep high reliability. They are applied for the electronic digital type of water flow meters. The reed switch sensor is just mounted simply on the conventional mechanical type flow meter. A small magnet is attached on a pointer of the water meter counter rotor. Inside the reed sensor two steel leaf springs make mechanical contact and apart repeatedly as rotation of flow meter counter. The counting electrical contact pulses can be converted as the water flow amount. The MCU sends the digital flow rate data to the server using the wireless communication network. But the digital data is occurred difference or won by chattering noise. The reed switch sensor contains chattering error by it self at the force equivalent position. The vibrations such as passing vehicle near to the switch sensor installed location causes chattering. In order to reduce chattering error, most system uses just software methods, for example using filter algorithm and also statistical calibration methods. The chattering errors were reduced by changing leaf spring structure using mechanical characteristics.