• Korean Journal of Computational Design and Engineering
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• v.5 no.2
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• pp.184-195
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• 2000

MDO (Multidisciplinary Design Optimization) methodology is an emerging new technology to solve a complicate structural analysis and design problem with a large number of design variables and constraints. In this paper MDO methodology is adopted through the use of computer aided systems such as Geometric Solid Modeller, Mesh Generator, CAD system and CAE system. And this paper introduces MDO methodology as a new method for structural analysis and design through the application to the structural design of flap drive system. In a MDO methodology application to the structural design of flap drive system, kinetodynamic analysis is done using a simple aerodynamic analysis model for the air flow over the flap surface instead of difficult aerodynamic analysis. Simultaneously the structural static analysis is done to obtain the optimum structural condition. And the structural buckling analysis for push pull rod is also done to confirm the optimum structural condition (optimum cross section shape of push pull rod).

• Archives of Reconstructive Microsurgery
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• v.14 no.2
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• pp.117-124
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• 2005

Purpose: To present our experience and design modification of an anterolateral thigh flap in soft tissue reconstruction. Materials and Methods: Between April of 2004 and May of 2005, 26 anterolateral thigh flaps were used in 26 patients. There were 22 males and 4 females between 23 and 60 years (mean, 40years). The mean follow-up period was 11($4{\sim}18$) months. All cases were a cutaneous flap. Twenty-two were musculocutaneous perforator flaps(85%) and 4 were septocutaneous perforator flaps(15%). Four flaps were used as a sensate flap. While the donor sites were closed directly in 14 cases(54%), 12 cases(46%) underwent skin grafting of the donor site. During the flap design, a triangular skin design was added to a vascular anastomosis site in 14(54%) patients and used as a roof of the tunnel. The healing period of the skin graft between those performed above the fascia and above the muscle were compared. Results: The average size of the flaps was $16{\times}9(11-20{\times}7-12)\;cm$. The overall flap success rate was 96%. Complications encountered were infection in 4 cases, and marginal skin necrosis in 1 case. The healing period was delayed with the infection in 3 of the 6 cases involving a skin graft over the fascia. All 14 cases with the triangular skin design survived, but there was 1 flap failure and 1 marginal necrosis in 12 cases without a triangular skin design. Conclusions: It may be better to undergo a skin graft above the muscle than above the fascia in covering a donor site defect, and to use a triangular skin design in order to prevent vascular insufficiency. An anterolateral thigh flap is a versatile flap for a soft tissue reconstruction because its thickness and volume can be adjusted to the extent of the defect with minimal donor site morbidity.

• Archives of Plastic Surgery
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• v.35 no.6
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• pp.692-697
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• 2008

Purpose: Gluteal perforator flap has evolved to one of the standard tools for coverage of pressure sore. We used this flap to cover the defect adjacent to the buttock. Methods: From September 2004 to August 2006, gluteal perforator flaps were performed in 3 patients with sore and 9 patients with tumor. We made the rule for free style design of the flap. First, the defect should be covered fully regardless of the shape or area. Second, the location of perforators was decided to maximize flap mobility. Third, the donor-site should be closed directly. Results: Successful reconstruction was fulfilled. In 2 cases, initial flap congestion was observed but medical leech was applied and it was resolved. Partial flap loss occurred in one case. Infection was observed in one case. But there were no major complications. Conclusion: Gluteal perforator flap is very good option for the reconstruction of the defects adjacent to the buttock.

• Archives of Plastic Surgery
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• v.48 no.1
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• pp.114-120
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• 2021

Background The pedicled anterolateral thigh (ALT) flap has become more popular for the reconstruction of soft-tissue defects in neighboring areas. Nonetheless, few studies in the literature have explored the use of this flap for trochanteric ulcer reconstruction. The aim of our study is to present the author's experience of utilizing the ALT flap, with a focus on technical elements regarding the flap design and the tunneling method to maximize the reach of the flap. Methods The medical records of patients who received pedicled ALT flaps for the reconstruction of trochanteric pressure sores were retrospectively reviewed. The patients' demographic data, operative details, and postoperative complications were evaluated. Results Between October 2018 and December 2019, 10 consecutive patients (age range, 13-45 years) underwent 11 pedicled ALT myocutaneous flaps for trochanteric pressure sore reconstruction. Each flap was designed around the most distal cutaneous perforator that was included in the proximal third of the skin paddle. The flaps ranged in size from 11×6 to 14×8 cm. The ALT flap was transposed through a lateral subcutaneous tunnel in five patients, while the open tunnel technique was used in six patients. All flaps survived, and no vascular compromise was observed. Conclusions The pedicled ALT flap is a safe and reliable option for reconstructing trochanteric pressure sores. An appropriate flap design and a good choice of the tunneling method are crucial for successful flap transposition.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.10
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• pp.667-676
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• 2015

Working displacement variation by elastic deformation of active Gurney flap which was operated on high frequency was observed. Flap-wise natural frequency was lower than mode analysis result and hinge boundary condition was identified to be the cause through the simple modal test. Design modification for increasing natural frequency was conducted for minimizing the elastic deformation at maximum 35 Hz operating condition which was design requirement condition. Brass bushing was applied instead of rotating bearing for gap minimization and Gurney flap design modification was conducted to increase of the flap-wise natural frequency. Design modification effect was validated by natural frequency comparison with mode analysis result and modal test result of design modification model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.916-921
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• 2014

In this paper, an improved small-scaled blade prototype was designed with the flap-driving mechanism classified as an active vibration reduction method, in order to reduce vibratory load in the helicopter. In detail, the previous Active Trailing-Edge Flap based on piezoelectric actuator, called SNUF(Seoul National University Flap), failed to achieve the target value (${\pm}4^{\circ}$) of the flap deflection angle. Therefore, the flap-driving mechanism design was improved, and a new piezoactuator was selected to accomplish the target value of the flap deflection angle in both static and rotating situations.

• Archives of Plastic Surgery
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• v.51 no.1
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• pp.126-129
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• 2024

The square flap method has been successful in releasing contracture bands at various body regions. However, the original square flap method alone may not be efficient in releasing long contracture bands. We, therefore, proposed an extended design to the traditional design, which is called the "square-plus flap." A 4-year-old girl presented with a postburn web-like contracture band over the right axilla. We marked a square flap technique at the center of the contracture band and then two additional Z-plasties were placed on both edges of the flap. After the release and securing of the square flap, the adjacent distal Z-plasty was then transposed and sutured in their new locations. We do not need to incise the proximal Z-plasty as we could achieve complete relaxation of the contracture band. This novel modification can be added to the plastic surgeon's armamentarium for releasing long postburn contracture bands involving distinct body regions.

• Archives of Reconstructive Microsurgery
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• v.18 no.1
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• pp.35-39
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• 2009

Purpose: Various techniques have been attempted for design of the flaps. However, there are some disadvantages. They have thin, pliable, and two dimensional methods. The aim of this study is to report usefulness of polyurethane foam dressing materials for three dimensional design of the digital island flap. Methods: From June of 2007 to september of 2008, 10 patients received digital island flap surgery for soft tissue defect of the finger. After minimal debridement of the wound, size and shape of the defect were measured using polyurethane foam. We used Medifoam-$5^{(R)}$ And then, designed this inset the wound. The flap was designed on the donor site with a arterial pedicle as the central axis according to size and shape. A full thickness skin graft from the groin is applied on the flap donor defect and secured with a tieover bolster dressing. Results: Reviewing sizes of the flaps, the length and width of flaps ranged from 1.5 to 3.3 cm and 1.0 to 2.5 cm. The PACS(Picture Archiving Communication System) program allows identification of the donor depth of finger. The distance for the soft tissue ranged from 4.3 mm to 6.7 mm. Mean depth of donor site was 5.3${\pm}$0.6 mm. Also, the thickness of Medifoam-$5^{(R)}$ ranged nearly 5 mm. On flap insetting, full-thickness skin graft was necessary. We did not experience any problems in the recipient site size either, regardless of the extended flaps. Conclusion: Polyurethane foam has many advantages over the more conventional templates. Refinements in flap design and surgical technique resulted in favorable functional and cosmetic results. Especially, for beginner, Polyurethane foam dressing material is a simple and safe tool and therefore is an excellent choice for design of the island flap.

• Archives of Reconstructive Microsurgery
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• v.21 no.1
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• pp.14-20
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• 2012

Purpose: Defect after ablation of hypopharyngeal cancer often requires reconstruction by free tissue transfer. Since neo-hypopharynx is totally buried, various methods have been suggested for monitoring. We propose a modified design of anterolateral thigh (ALT) free flap for reconstruction of pharyngolaryngectomy defect, which has an exteriorized part for clinical monitoring and allows for primary closure. Materials and Methods: Three consecutive patients with hypopharyngeal cancer were reconstructed with ALT flap with modified design: 1) distal part of flap was elongated into fusiform shape and used as exteriorized monitoring segment with a deepithelized bridge and 2) proximal part was designed as curve so the maximum width of the flap was reduced to less than 10 cm. Results: Patient 1, 2 had uneventful postoperative course with healthy skin color and fresh pin prick bleeding. In patient 3, defect after cancer ablation was shorter than usual and deepithelized bridge was longer. When the general hemodynamic status of the patient was aggravated in postoperative course, the color of monitoring skin was changed. Viability of the whole flap was confirmed by endoscopy. However, leakage developed after 3 weeks and repair was necessary. In all patients the donor sites were closed primarily. Conclusion: By the modified design of ALT flap, clinical monitoring can be possible by examining exteriorized monitoring flap and also donor site can be closed primarily. However possibility of false positive exists and technical caution and patient selection is needed because of danger of leakage.

• 한국전산유체공학회:학술대회논문집
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• 2000.10a
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• pp.32-38
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• 2000

Wing flap deflection angles of a supersonic transport are optimized to improve transonic cruise performance. For this end, a numerical optimization method is adopted using a three-dimensional unstructured Euler code and a discrete adjoint code. Deflection angles of ten flaps; five for leading edge and five fur railing edge, are employed as design variables. The elliptic equation method is adopted for the interior grid modification during the design process. Interior grid sensitivities are neglected for efficiency. Also tested is the validity of the approximate gradient evaluation method for the present design problem and found that it is applicable for loading edge flap design in cases of no shock waves on the wing surface. The BFGS method is used to minimize the drag with constraints on the lift and upper surface Mach numbers. Two design examples are conducted; one is leading edge flap design, and the other is simultaneous design of leading edge and trailing edge flaps. The latter gave a smaller drag than the former by about two counts.