• Structural Engineering and Mechanics
• /
• v.32 no.3
• /
• pp.399-406
• /
• 2009

A three-dimensional panel system, which was offered as a new method for construction in Jordan using relatively high strength modular panels for walls and ceilings, is investigated in this paper. The panel consists of two steel meshes on both sides of an expanded polystyrene core and connected together with a truss wire to provide a 3D system. The top face of the ceiling panel was pored with regular concrete mix, while the bottom face and both faces of the wall panels were cast by shotcreting (dry process). To investigate the structural performance of this system, an extensive experimental testing program for ceiling and wall panels subjected to static and dynamic loadings was conducted. The load-deflection curves were obtained for beam and shear wall elements and wall elements under transverse and axial loads, respectively. Static and dynamic analyses were conducted, and the performance of the proposed structural system was evaluated and compared with a typical three dimensional reinforced concrete frame system for buildings of the same floor areas and number of floors. Compressive strength capacity of a ceiling panel is determined for gravity loads, while flexural capacity is determined under the effect of wind and seismic loading. It was found that, the strength and serviceability requirements could be easily satisfied for buildings constructed using the three-dimensional panel system. The 3D panel system is superior to that of conventional frame system in its dynamic performance, due to its high stiffness to mass ratio.

• The Journal of Korean Physical Therapy
• /
• v.20 no.1
• /
• pp.17-22
• /
• 2008

Purpose: This study examined whether or not changes in the static and dynamic balance performance occur during pregnancy. Methods: Fourteen pregnant women and fourteen non-pregnant women volunteered to participate in the study. All subjects were tested for their balance performance on the Chattecx Balance System (Chattanooga Group, Inc., USA) under a two platform condition: stable platform and dynamic platform(forward-backward sliding and tilting). The Chattecx Balance System was measured using the postural sway index, anterior-posterior sway index, and medial-lateral sway index. Results: There was a significant difference in the postural sway index and anterior posterior sway index in the static and dynamic platform condition between the pregnant and non-pregnant women (p<0.05). However, there was no difference in the medial-lateral sway index. Conclusion: The postural sway index and anterior-posterior sway index decreases during pregnancy.

• Steel and Composite Structures
• /
• v.22 no.4
• /
• pp.777-796
• /
• 2016

In this paper, the behavior of woven E-glass fabric composite laminate was experimentally investigated under quasi-static indentation and high velocity impact by flat-ended, hemispherical, conical (cone angle of $37^{\circ}$ and $90^{\circ}$) and ogival (CRH of 1.5 and 2.5) cylindrical perforators. Moreover, the results are compared in order to explore the possibility of extending quasi-static indentation test results to high velocity impact test results in different characteristics such as perforation mechanisms, performance of perforators, energy absorption, friction force, etc. The effects of perforator nose shape, nose length and nose-shank connection shapes were investigated. The results showed that the quasi-static indentation test has a great ability to predict the high velocity impact behavior of the composite laminates especially in several characteristics such as perforation mechanisms, perforator performance. In both experiments, the highest performance occurs for 2.5 CRH projectile and the lowest is related to blunt projectiles. The results show that sharp perforators indicate lower values of dynamic enhancement factor and the flat-ended perforator represents the maximum dynamic enhancement factor among other perforators. Moreover, damage propagation far more occurred in high velocity impact tests then quasi-static tests. The highest damage area is mostly observed in ballistic limit of each projectile which projectile deviation strongly increases this area.

• Journal of Korean Physical Therapy Science
• /
• v.19 no.1
• /
• pp.55-62
• /
• 2012

Objectives : The purpose of this study was to determine the effects of high heeled shoes on the static & dynamic balance performance and electromyography(EMG) of back and lower extremity muscles. Materials & Methods : Sixteen women participated in this study. Subjects were composed two groups with LL shoes group and higher heel shoes group. We carried out Romberg's test and muscle activity of left and right Paraspinalis, Quadriceps femoris, Tibialis anterior, Gastrocnemius muscles by EMG in order to determine static balance performance according heel height. Using by Biorescue(Incenierie company), we trained subject to transfer of COG each direction(Anterior, posterior, Right, Left), we carried out this test for distance, surface, distance/surface in order to determine dynamic balance performance according heel height. The data were analyzed by independent t-test between lower and high heel height using SPSS(ver. 17.0)/PC program. Results : There was significant difference of distance(p<.05) of weight perturbation between lower and high group in dynamic balance performance and EMG value of left Gastrocnemius(p<.05), both Tibialis anterior(p<.05) muscle in static balance performance. Conclusions : Height of heel has effect on dynamic balance performance in distance of the Anterior, posterior direction. EMG of Gastrocnemius and Tibialis anterior muscles were affected by Romberg's test.

• Journal of Korean Physical Therapy Science
• /
• v.30 no.1
• /
• pp.23-30
• /
• 2023

Background: While agility is a critical factor in the performance of sport in the court field, due to the diversity of agility occurrences, it is generally difficult to develop by strength and conditioning training. Previous study reported the correlation with the static balance and agility. However, the correlation between dynamic balance and agility is insufficient. It is necessary to study how static and dynamic balance affect agility respectively, for agility development. Design: Cross sectional correlational study design Methods: Twenty young women participated in the study. Three tests were used : one leg stance(static balance),Y-balance(dynamic balance), side-step(agility). One leg stance measured time, Y-balance measured distance, and side-step measured number of times. Correlation between balance and agility was used by Pearson Correlation. Results: One leg stance and side steps were shown to be not correlated. The Y balance and the side step showed with a moderate positive correlation. Conclusion: Agility is a decisive factor in fast-moving sports performance, which is generally difficult to improve with muscle strength and conditioning training. Since the correlation between dynamic balance and agility was found in this study, the importance of dynamic balance was found to improve agility to promote coordination.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.6 no.2
• /
• pp.21-28
• /
• 2002

Ductile behavior and strength of concrete-filled steel(CFS) piers was supported by many quasi-static cyclic loading tests. This test method, however, only estimates the member′s deformation capacity under escalating and repetitive displacement and ignores dynamic and random aspects of an earthquake load. Therefore, to understand complete seismic behavior of the structure against an earthquake, dynamic tests such as shaking table test and pseudo-dynamic tests are required as well as quasi-static tests. In this paper, following "Seismic Performance of Concrete-Filled Steel Piers Part I : Quasi-Static Cyclic Loadint Test", the seismic behavior of CFS and steel piers designed for I-Soo overpass in Seoul in investigated by the pseudo-dynamic test. In addition, the residual strength of both piers after an earthquake is estimated by the quasi-static test. The results show that both piers have satisfactory ductility and strength against well-known EI Centro earthquake although the CFS pier has better strength and energy dissipation than the steel pier.

• Steel and Composite Structures
• /
• v.2 no.2
• /
• pp.113-128
• /
• 2002

The performance of steel MRF with rigid connections, proportioned by adopting different capacity design criteria, is evaluated in order to highlight the effectiveness of static non-linear procedure in predicting the structural seismic behavior. In the framework of the performance-based design, some considerations are made on the basis of the results obtained by both dynamic time histories and push-over analyses, particularly with reference to the damage level and the structure ability to withstand a strong earthquake.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.3
• /
• pp.85-97
• /
• 2000

In this paper, static and dynamic shift control stategies of CVT speed ratio are suggested. For the static shift control, in order to operate engine on the optimal operating region, a fuzzy control logic is used. In the fuzzy logic, S- factor that is defined as a degree of sportiness is introduced. Simulation results show that the static shift control strategy based on the fuzzy logic selects the optimal operating point automatically between the economy and the sporty mode corresponding to the driver's desire and the driving condition. For the dynamic shift control strategy, a shift speed map is suggested which determines the shift sped as fast or slow based on Δi, the difference between the desired speed ratio id and the actual speed ratio i, and throttle opening. It is seen from the simulation results that the CVT shift speed is determined by the dynamic shift control strategy to provide appropriate performance and comfort for the driver's demand and driving condition. Additionally, experiments are performed to investigate the dynamic performance of the shift speed for the lift foot up. From the experimental results, it is found that improved shift feeling can be obtained by the dynamic shift control strategy when lift foot up occurs.

• Structural Engineering and Mechanics
• /
• v.33 no.1
• /
• pp.31-46
• /
• 2009

An anisotropic damage mechanics approach is introduced which models the static and dynamic behavior of mass concrete in 3D space. The introduced numerical approach is able to model non-uniform cracking within the cracked element due to cracking in Gaussian points of elements. The validity of the proposed model is considered using available experimental and theoretical results under the static and dynamic loads. No instability and stress locking is observed in the conducted analyses. The Morrow Point dam is analyzed including dam-reservoir interaction effects to consider the nonlinear seismic behavior of the dam. It is found that the resulting crack profiles are in good agreement with those obtained from the smeared crack approach. It is concluded that the proposed model can be used in nonlinear static and dynamic analysis of concrete dams in 3D space and enables engineers to define the damage level of these infrastructures. The performance level of the considered system is used to assess the static and seismic safety using the defined performance based criteria.

• Structural Engineering and Mechanics
• /
• v.15 no.6
• /
• pp.735-752
• /
• 2003

The quasi-static and dynamic responses of a linear viscoelastic circular beam on Winkler foundation are studied numerically by using the mixed finite element method in transformed Laplace-Carson space. This element VCR12 has 12 independent variables. The solution is obtained in transformed space and Schapery, Dubner, Durbin and Maximum Degree of Precision (MDOP) transform techniques are employed for numerical inversion. The performance of the method is presented by several quasi-static and dynamic example problems.