• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.146-152
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• 2002

The steel shows plastic deformation after the yield point exceeds. Because of overloads, the plastic deformation occurs at the interior support of a continuous bridge. The plastic deformation is concentrated at the interior support, and the permanence deformation at the interior support remains after loads pass. Because local yielding causes the positive moment at the interior support, it is called "auto moment". Auto moment redistributes the elastic moment. Because of redistribution, auto moment decreases the negative moment at the interior support of a continuous bridge. In this paper, the moment-rotation curve from Schalling is used. The Plastic rotation is computed by using Beam-line method, and auto moment is calculated based on the experiment curve. The design example is presented using limit state criterion.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.1
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• pp.99-105
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• 2018

PURPOSE: The aim of this study was to evaluate the concurrent validity and clinical usefulness of the universal plastic goniometer to measure the range of motion of the internal and external rotation of the hip joint using the three dimensional motion analysis which can analyze the joints and segment movements in the most objective and quantitative method. METHODS: Clinical and kinematic data were collected from thirty individuals using a universal plastic goniometer and a ten camera motion analysis system. Passive hip rotation range was obtained three trials for left and right hip joints using two measure methods simultaneously. RESULTS: There were significant differences between all matching measures of the two measures of internal and external rotation of the hip joint (p<.05). The relationship between the two tests for all measurements of the internal and external rotation of the hip was statistically significant with correlation coefficient form r=.87 to .96. (p<.01). CONCLUSION: Clinical measurement of the internal and external rotation of the hip using a universal plastic goniometer is effective to assess the hip condition. However, application of universal plastic goniometer requires careful attention in more accurate evaluation and research verification of the internal and external rotation of hip joint.

• Structural Engineering and Mechanics
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• v.91 no.3
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• pp.301-313
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• 2024

Plastic buckling of tubular columns has been attributed to rotational instability of plastic hinges. The present study aimed to characterize the plastic hinges for two different grades of strain-hardening, examined in mild-steel (MS) and stainless-teel (SS) tubes with un-strengthened and strengthened conditions. At the primary stage, the formerly tested experimental specimens were simulated using full-scale FE models considering nonlinear response of the materials, then to estimate the characteristics of the plastic hinges, a meso model was developed from the critical region of the tubes and the moment-rotation diagrams were depicted under pure bending conditions. By comparison of the relative rotation diagram obtained by the full-scale models with the critical rotation under pure bending, the length and critical rotation of the plastic hinges under eccentric axial load were estimated. The stress and displacement diagrams indicated the mechanism of higher energy absorption in the strengthened tubes, compared to unstrengthened specimens, due to establishment of stable wrinkles along the tubes. The meso model showed that by increasing the critical rotation in the strengthened MS tube equal to 1450%, the energy absorption of the tube has been enhanced to 2100%, prior to collapse.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.433-439
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• 2000

Reinforced concrete beams show increased ductile behavior when the compressive concrete is confined with transverse steel. In the inelastic range, the most variations of ductile behaviour are defined the equivalent length of the plastic hinge and the plastic hinge rotation. In an investigation to study the influence of such confinement, sixteen reinforced concrete beams were tested in flexure and the deflections noted at all stages of loading. For all the beams tested, the plastic hinge rotation have been computed and the effect of confinement on the same examined. The conclusions are summarized as follows: The equivalent lengths of the plastic hinge are ranged within the effective depth comparatively. The ability of the plastic hinge rotation of the reinforced concrete beams confined with transverse steel are enlarged when transverse reinforcement content are increased, but the spaces are more important as the shear force are largely increased.

• Archives of Reconstructive Microsurgery
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• v.16 no.1
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• pp.23-29
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• 2007

The reconstruction of deep soft tissue defect such as pressure sore has difficult problems. Myocutaneous flaps have been used commonly as the best coverage method for pressure sore. But, they have several drawbacks such as sacrifice of functional muscle, high morbidity of the donor sites and bulkiness at the recipient site. The concepts of perforator flap has recently developed and widely used to overcome these disadvantages. Between March 2005 to July 2006, we have treated 9 patients who had pressure sore using perforator based fasciocutaneous island rotation flap. Preoperative unidirectional Doppler was used in all cases. Mean number of perforator vessels was 3.8 and flap sizes were from $7{\times}5\;cm$ to $14{\times}13\;cm$. Rotation angles of flap were from 90 degree to 180 degree. In all cases, donor sites were closed primarily. All flap survived completely and postoperative complications were wound dehiscence in 1 case, wound infection in 3 cases. The mean postoperative follow up period was 15.7 months and recurrence was not reported. We could decrease donor site morbidity and cover wound sites easily by using flap rotation and get robust blood supply without sacrifice of functional muscle. Fasciocutaneous perforator island rotation flap would be very useful for various pressure sore treatment.

• Archives of Plastic Surgery
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• v.49 no.1
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• pp.39-42
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• 2022

Bilateral pectoralis major myocutaneous (PMMC) flaps are commonly used to reconstruct large chest wall defects. We report a case of large chest wall defect reconstruction using bilateral PMMC flaps augmented with axillary V-Y advancement rotation flaps for additional flap advancement. A 74-year-old male patient was operated on for recurrent glottic squamous cell carcinoma. Excision of the tumor resulted in a 10×10 cm defect in the anterior chest wall. Bilateral PMMC flaps were raised to cover the chest wall defect. For further flap advancement, V-Y rotation advancement flaps from both axillae were added to allow complete closure. All flaps survived completely, and postoperative shoulder abduction was not limited (100° on the right side and 92° on the left). Age-related skin redundancy in the axillae enabled the use of V-Y rotation advancement flaps without limitation of shoulder motion. Bilateral PMMC advancement flaps and the additional use of V-Y rotation advancement flaps from both axillae may be a useful reconstructive option for very large chest wall defects in older patients.

• Journal of Korean Society of Steel Construction
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• v.23 no.4
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• pp.405-415
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• 2011

For the safe seismic design of buildings, it is necessary to predict the plastic deformation demands of the members as well as the story drift ratio. In the present study, a simple method of estimating the beam plastic rotation was developed for special-moment-resisting steel frame structures designed with strong column-weak beam behavior. The proposed method uses elastic analysis rather than nonlinear analysis, which is difficult to use in practice. The beam plastic rotation was directly calculated based on the results of the elastic analysis, addressing the moment redistribution, the column and joint dimensions, the movement of the plastic hinge, the panel zone deformation, the gravity load, and the strain-hardening behavior. In addition, the rocking effect of the braced frame or core wall on the beam plastic rotation was addressed. For verification, the proposed method was applied to a six-story special-moment frame designed with strong column-weak beam behavior. The predicted plastic rotations of the beams were compared with those that were determined via nonlinear analysis. The beam plastic rotations that were predicted using the proposed method correlated well with those that were determined from the nonlinear pushover analysis.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.825-832
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• 2010

Although a critical section reaches its flexural strength in reinforced concrete structures, the structure does not always fail because moment redistribution occurs during the formation of plastic hinges. Inelastic deformation in a plastic hinge region results in plastic rotation. A plastic hinge mainly depends on material characteristics. In this study, a plastic hinge length and plastic rotation are evaluated using the flexural curvature distribution which is derived from the material models given in Eurocode 2. The influence on plastic capacity the limit values of the material model used, that is, ultimate strain of concrete and steel and hardening ratio of steel(k), are investigated. As results, it is appeared that a large ultimate strain of concrete and steel is resulting in large plastic capactiy and also as a hardening ratio of steel increases, the plastic rotation increases significantly. Therefore, a careful attention would be paid to determine the limit values of material characteristics in the RC structures.

• Journal of Korean Society of Steel Construction
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• v.20 no.5
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• pp.617-624
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• 2008

Well-designed steel moment connections will undergo local buckling before they exhaust their available rotation capacity, and inelastic post-buckling deformation plays a major role in defining the connection rotation capacity. An approximate analytical method to model strength degradation and failure of beam plastic hinges due to local buckling and estimation of the seismic rotation capacity of fully restrained beam-column connections in special steel moment-resisting frames under both monotonic and cyclic loading conditions is proposed in this study. This method is based on the plastic mechanism and a yield line plastic hinge (YLPH) model whose geometry is determined using the shapes of the buckled plastic hinges observed in experiments. The proposed YLPH model was developed for the improved WUF-W and RBS connections and validated in comparison with experimental data. The effects of the beam section geometric parameters on the rotation capacity were discussed in the companion paper (parametric studies).

• Archives of Plastic Surgery
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• v.33 no.2
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• pp.181-186
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• 2006

Myocutaneous flaps have improved the management of soft tissue defects on buttocks and lower extremity. However, there are several inherent disadvantages of muscle flaps such as functional deficits of the donor sites and the bulkiness at the recipient site. To overcome these disadvantages, we have used perforator-based fasciocutaneous rotation flaps for reconstruction of the buttock and lower extremity defects. From March 2003 to February 2005, we have treated 14 patients using perforator-based fasciocutaneous rotation flaps. 10 flaps were based on perforators of the gluteus maximus muscle, and 4 flaps were nourished by perforators from the tibialis anterior and posterior system. The mean postoperative follow-up period was about 1 year. The technique involves localization of the flap perforators preoperatively with a Doppler. The flaps were elevated superficial to the fascia with preservation of one to three perforators. The donor site is then closed primarily. All flaps completely survived and there was no perioperative complications. There was no functional disability of the donor area with esthetically pleasing results. Perforator-based fasciocutaneous rotation flaps for the reconstruction of buttock and lower extremity defects are excellent alternatives to musculocutaeous flaps. The vascularity of the flaps is robust and dissection is technically easy. Perforator flaps do not require sacrificing muscles, but provide sufficient volume and are durable Furthermore, these flaps result in less scar formation and allow more liberal dissection with safety. We conclude that perforator-based fasciocutaneous rotation flaps are very useful for reconstruction of the buttock and lower extremity.