• Smart Structures and Systems
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• 제5권3호
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• pp.291-316
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• 2009

Damage detection using structural classical deflection flexibility has received considerable attention due to the unique features of the flexibility in the last two decades. However, for relatively complex structures, most methods based on classical deflection flexibility fail to locate damage sites to the exact members. In this study, for structures whose members are dominated by axial forces, such as truss structures, a more feasible flexibility for damage detection is proposed, which is called the Axial Strain (AS) flexibility. It is synthesized from measured modal frequencies and axial strain mode shapes which are expressed in terms of translational mode shapes. A damage indicator based on AS flexibility is proposed. In addition, how to integrate the AS flexibility into the Damage Location Vector (DLV) approach (Bernal and Gunes 2004) to improve its performance of damage localization is presented. The methods based on AS flexbility localize multiple damages to the exact members and they are suitable for the cases where the baseline data of the intact structure is not available. The proposed methods are demonstrated by numerical simulations of a 14-bay planar truss and a five-story steel frame and experiments on a five-story steel frame.

• Structural Engineering and Mechanics
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• 제36권5호
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• pp.643-667
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• 2010

The classical flexibility difference method detects damage by observing the difference of conventional deflection flexibility matrices between pre- and post-damaged states of a structure. This method is not able to identify multiple damage scenarios, and its criteria to identify damage depend upon the boundary conditions of structures. The key point behind the inability and dependence is revealed in this study. A more feasible flexibility for damage detection, the Angle-between-String-and-Horizon (ASH) flexibility, is proposed. The physical meaning of the new flexibility is given, and synthesis of the new flexibility matrix by modal frequencies and translational mode shapes is formulated. The damage indicators are extracted from the difference of ASH flexibility matrices between the pre- and post-damaged structures. One feature of the ASH flexibility is that the components in the ASH flexibility matrix are associated with elements instead of Nodes or DOFs. Therefore, the damage indicators based on the ASH flexibility are mapped to structural elements directly, and thus they can pinpoint the damaged elements, which is appealing to damage detection for complex structures. In addition, the change in the ASH flexibility caused by damage is not affected by boundary conditions, which simplifies the criteria to identify damage. Moreover, the proposed method can determine relatively the damage severity. Because the proposed damage indicator of an element mainly reflects the deflection change within the element itself, which significantly reduces the influence of the damage in one element on the damage indicators of other damaged elements, the proposed method can identify multiple damage locations. The viability of the proposed approach has been demonstrated by numerical examples and experimental tests on a cantilever beam and a simply supported beam.

• The Journal of Korean Physical Therapy
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• 제33권5호
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• pp.217-223
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• 2021

Purpose: This study sought to identify the effects of coordinative locomotor training (CLT) using elastic bands on the flexibility and body alignment of right-handed baseball players in elementary school. Methods: The subjects were 20 instructed right-handed baseball players in elementary school. They were classified into the experimental group with 10 players (n=10) to be given coordinative locomotor training using elastic bands and the control group with 10 players (n=10). Flexibility was measured by the sit and reach exercise. Body alignment was measured using formetric 4D method to measure the trunk imbalance angle (TI), trunk torsion angle (TT), pelvic tilt angle (PTi), pelvic torsion angle (PTo), pelvic rotation angle (PR), kyphotic angle (Ky), and lordotic angle (Lo). Results: There was a significant increase in the flexibility within the experimental group (p<0.05). after the intervention. There was also a significant increase in the difference between the experimental group and the control group (p<0.05). There was a significant decrease in PR during body alignment in the experimental group after intervention (p<0.05). An analysis of the differences between groups showed a significant decrease in the PR of the experimental group compared to the control group (p<0.05). Conclusion: These findings show that coordinative locomotor training using elastic bands would be effective for enhancing the flexibility and pelvic rotation of elementary school right-handed baseball players.

• Architectural research
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• 제15권4호
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• pp.191-200
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• 2013

Since Modern Movement flexibility has been one of the most attractive words in architecture. However, "overprovision first, division later" has been the most prevailing design method for spatial flexibility, and many of buildings designed for flexible use are practically quite inflexible due to insufficient building systems or/and irresponsible planning. There have been two dominant strategies to achieve architectural flexibility: multi-functionality and polyvalence. These two approaches, which point contradictory directions, actually reflect the difficulty in providing a proper form of architectural flexibility. Multi-functionality can afford changeable environments with satisfying spatial conditions; however it lacks tolerance to accommodate other uses but intended functions by architects. Meanwhile, flexibility by a polyvalent form relies on the vague anticipation of user's various interpretations. In this study by looking up these two different standpoints and historical precedents flexibility in architecture is carefully scrutinized focused on the contradiction, and as an alternative for architectural flexibility contextual relations is proposed. Unlike both multi-functionality and polyvalence, which produce flexibility by changing its own properties, manipulating contextual relations infuses flexibility into space by changing the properties of a building, not of its individual room. By using this contextual relations method, a community-centered school in Manhattan, NY, which was in danger of being closed because of its academic failure, is represented as a flexible space.

• Steel and Composite Structures
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• 제18권5호
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• pp.1215-1237
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• 2015

The majority of connections in moment resisting frames are considered as being fully-rigid. Consequently, the real behavior of the connection, which has some level of flexibility, is ignored. This may result in inaccurate predictions of structural response. This study investigates the influence of flexibility of the extended end-plate connections in the steel moment frames. This is done at two levels. First, the actual micro-behavior of extended end-plate moment connections is explored with respect to joint flexibility. Then, the macro-behavior of frames with end-plate moment connections is investigated using modal, nonlinear static pushover and incremental dynamic analyses. In all models, the P-Delta effects along with material and geometrical nonlinearities were included in the analyses. Results revealed considerable differences between the behavior of the structural frame with connections modeled as fully-rigid versus those when flexibility was incorporated, specifically difference occurred in the natural periods, strength, and maximum inter-story drift angle.

• Structural Engineering and Mechanics
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• 제5권5호
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• pp.523-528
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• 1997

Stiffness and flexibility equations are combined in the buckling analysis of a braced structure - stiffness for the original structure and flexibility for the bracing. Choosing a flexibility formulation for the bracing gives a very compact computational problem. It also gives theoretical insights into the behaviour of the braced structure.

• Industrial Engineering and Management Systems
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• 제14권3호
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• pp.236-247
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• 2015

This study aims to examine the effects of industrial clustering and manufacturing flexibility on innovation capability and operational performance. This study follow a survey method to collect data pertaining to the phenomena of industrial clustering, manufacturing flexibility, innovation capability, and operational performance by utilizing a single respondent design. A total of 124 Indonesian manufacturing SMEs are taken to test the proposed theoretical model by utilizing covariance-based structural equations modeling approach. It was found that both industrial clustering and manufacturing flexibility was positively associated with operational performance and innovation capability as well. In addition, innovation capability may account for the effects of industrial clustering and manufacturing flexibility on operational performance. This implies that manufacturing SMEs have to reorient their production and operation perspectives, including agglomerate with other similar or related SMEs to develop and utilize their own resources. The SMEs also need to possess some degree of manufacturing flexibility in respond to the uncertain environment and market changes. In addition, the SMEs should put a greater emphasize to use industrial cluster and manufacturing flexibility benefits to generate innovation capability to achieve high performance.

• The Journal of Korean Physical Therapy
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• 제34권1호
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• pp.38-44
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• 2022

Purpose: The purpose of this study was to investigate the effects of complex training on injury, flexibility, and muscle stiffness in high school male football players. Methods: A total of 60 football players were included in the study and were divided into three groups viz. the complex training group (CTG), 11+ training group (11+TG), and traditional training group (TTG). Injuries were recorded based on the prospective investigation method after starting the study, and the flexibility and muscle stiffness of the subjects were evaluated. Results: The research results showed that the injury rate per match was significantly lower in the CTG and 11+TG than the TTG. In the CTG, the flexibility of the hamstrings significantly increased and the stiffness of the rectus femoris (RF), biceps femoris (BF), and tensor fascia latae (TFL) muscles significantly decreased (p<0.05). In the 11+TG, the stiffness of the RF significantly decreased (p<0.05). In the TTG, the flexibility of the hamstrings significantly increased (p<0.05). Hamstring flexibility showed a significantly higher increase in the CTG and TTG compared to the 11+TG (p<0.05). Also, the stiffness of the RF and TFL muscles showed a significantly higher decrease in the CTG compared to the 11+TG and TTG (p<0.05). The stiffness of the BF muscles too showed a more significant decrease in the CTG compared to the TTG (p<0.05). Conclusion: The complex training method of the Fédération International de Football Association (FIFA) 11+ and self-myofascial release (SMFR) as a warm-up program, prevent injuries, enhance flexibility, and lower muscle stiffness of football players in high school. Thus, it is necessary to ensure the widespread use of the complex training program by instructors and players under the supervision of the Korea Football Association (KFA), given its reliability in preventing injuries and improving the performance of football players.

• Structural Engineering and Mechanics
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• 제65권1호
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• pp.99-110
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• 2018

The focus of this paper is on the elements with stable open cracks. To analyze plane problems, two triangular elements with three and six nodes are formulated using force method. Flexibility matrices of the elements are derived by combining the non-cracked flexibility and the additional one due to crack, which is computed by utilizing the local flexibility method. In order to compute the flexibility matrix of the intact element, a basic coordinate system without rigid body motions is required. In this paper, the basic system origin is located at the crack center and one of its axis coincides with the crack surfaces. This selection makes it possible to formulate elements with inclined cracks. It is obvious that the ability of the suggested elements in calculating accurate natural frequencies for cracked structures, make them applicable for vibration-based crack detection.

• 한국심리학회지:학교
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• 제18권2호
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• pp.197-220
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• 2021

본 연구에서는 초등교사의 성인애착이 교사가 지각한 교사-학생 관계에 미치는 영향에서 인지적 유연성과 적극적 대처가 매개하는지 검증하였다. 경기도에서 근무하는 203명의 초등교사를 대상으로 자기보고식 설문을 실시하였으며, 측정도구로 성인애착, 인지적 유연성, 적극적 대처, 교사-학생 관계 척도를 사용하였고, 수집된 자료는 SPSS 23.0과 SPSS Macro를 이용하여 분석하였다. 본 연구의 결과는 다음과 같다. 첫째, 초등교사의 성인애착과 교사가 지각한 교사-학생 관계를 인지적 유연성이 매개하는 것으로 나타났다. 이는 초등교사의 성인애착이 안정적일수록 인지적 유연성이 증가하여 교사-학생 관계가 향상됨을 의미한다. 둘째, 인지적 유연성과 적극적 대처의 매개효과를 함께 고려할 때, 초등교사의 성인애착과 교사가 지각한 교사- 학생 관계를 적극적 대처가 매개하지 않는 것으로 나타났다. 성인애착이 적극적 대처로 가는 직접경로가 유의미하지 않음을 의미한다. 셋째, 초등교사의 성인애착과 교사가 지각한 교사-학생 관계를 인지적 유연성과 적극적 대처가 순차적으로 매개함을 확인하였다. 즉, 초등교사의 애착이 안정적일수록 인지적 유연성이 높아져 적극적 대처를 하게 되므로 교사가 학생과의 관계를 더욱 긍정적으로 지각하게 된다는 것이다. 이러한 연구결과를 바탕으로 본 연구의 의의와 제한점을 밝히고, 후속 연구를 위한 제언을 논의하였다.