• Journal of the Korea institute for structural maintenance and inspection
• /
• v.8 no.4
• /
• pp.175-183
• /
• 2004

The most important element is a rise ratio when regarding beauty and economics of arch bridges. Only the effect of dead load has been considered to decide the rise ratio. In this study, when going over the rise ratio of arch bridges, examined the problems, that the determination of the rise ratio by the dead load has, by adding the factor of a determination of optimum rise ratio, which is not only the effect of the dead load that has been currently considered but also the problem with respect to dynamic stability that is now taken seriously. Synthetically, when deciding rise ratio that is investigated in basic step of design, it is necessary to consider the evaluation dynamic stability.

• Journal of Korean Association for Spatial Structures
• /
• v.22 no.2
• /
• pp.57-64
• /
• 2022

In this paper, the physical model and governing equations of a shallow arch with a moving boundary were studied. A model with a moving boundary can be easily found in a long span retractable roof, and it corresponds to a problem of a non-cylindrical domain in which the boundary moves with time. In particular, a motion equation of a shallow arch having a moving boundary is expressed in the form of an integral-differential equation. This is expressed by the time-varying integration interval of the integral coefficient term in the arch equation with an un-movable boundary. Also, the change in internal force due to the moving boundary is also considered. Therefore, in this study, the governing equation was derived by transforming the equation of the non-cylindrical domain into the cylindrical domain to solve this problem. A governing equation for vertical vibration was derived from the transformed equation, where a sinusoidal function was used as the orthonormal basis. Terms that consider the effect of the moving boundary over time in the original equation were added in the equation of the transformed cylindrical problem. In addition, a solution was obtained using a numerical analysis technique in a symmetric mode arch system, and the result effectively reflected the effect of the moving boundary.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.8 s.227
• /
• pp.1237-1244
• /
• 2004

The orthodontic surgery including lingual orthodontics has recently attracted a person's attention due to its functional and esthetic appreciation. The skeletal anchorage with the miniscrew is newly adopted in the lingual orthodontics to assist the upholding ability. The appliciation needs to understand the mechanism of the orthodontic appliance and its related orthodontic correction for optimal orthodontic treatment. There is, however, few information about the qualitative and quantitative effect of the orthodontic appliance with the miniscrew has not been well identified. In this paper, three dimensional finite element analysis is introduced to the lingual orthodontics in order to investigate the effect of the anterior retraction force on the miniscrew and transpalatal arch wire. The analysis determines the adequate location of the miniscrew and the point of force application of the anchorage system in the lingual orthodontics. The analysis results demonstrate the effect of the position of the miniscrew and the transpalatal arch wire on the lingual orthodontics.

• Steel and Composite Structures
• /
• v.22 no.4
• /
• pp.855-874
• /
• 2016

In this paper, it is aimed to evaluate the earthquake angle influence on the seismic performance of steel highway bridges. Upper-deck steel highway bridge, which has arch type load bearing system with a total length of 216 m, has been selected as an application and analyzed using finite element methods. The bridge is subjected to 1992 Erzincan earthquake ground motion components in nineteen directions whose values range between 0 to 90 degrees, with an increment of 5 degrees. The seismic weight is calculated using full dead load plus 30% of live load. The variation of maximum displacements in each directions and internal forces such as axial forces, shear forces and bending moments for bridge arch and deck are attained to determine the earthquake angle influence on the seismic performance. The results show that angle of seismic input motion considerably influences the response of the bridge. It is seen that maximum arch displacements are obtained at X, Y and Z direction for $0^{\circ}$, $65^{\circ}$ and $5^{\circ}$, respectively. The results are changed considerably with the different earthquake angle. The maximum differences are calculated as 57.06%, 114.4% and 55.71% for X, Y and Z directions, respectively. The maximum axial forces, shear forces and bending moments are obtained for bridge arch at $90^{\circ}$, $5^{\circ}$ and $0^{\circ}$, respectively. The maximum differences are calculated as 49.12%, 37.37% and 51.50%, respectively. The maximum shear forces and bending moments are obtained for bridge deck at $0^{\circ}$. The maximum differences are calculated as 49.67%, and 49.15%, respectively. It is seen from the study that the variation of earthquake angle effect the structural performance of highway bridges considerably. But, there is not any specific earthquake angle of incidence for each structures or members which increases the value of internal forces of all structural members together. Each member gets its maximum value of in a specific angle of incidence.

• Journal of Bio-Environment Control
• /
• v.2 no.2
• /
• pp.89-98
• /
• 1993

The purpose of this study was to investigate crop growth responses under various rain shelters which were devised to improve the indoor environment in summer season. For developing the proper type of rain shelter, the improved rain shelters with the roof of saw - tooth type(saw-tooth type) and 3 span-arch type(improved arch type) were compared with the conventional one with the roof of single arch type(conventional arch type) and no rain shelter (open field ). The results were summarized as follows ; 1. The air temperature in the improved arch type was 4$^{\circ}C$ and 1$^{\circ}C$ lower than those in the conventional arch type and the saw - tooth type, respectively. 2. The air temperature drop by the evaporative cooling + improved drainage was 1.3$^{\circ}C$ which was 0.9$^{\circ}C$lower than that by the improved drainage only. 3. The effect of labour saving in the saw-tooth type was superior to any other type because its frames were used as props and the labour for ventilation was not needed. 4. The highest marketable yield of tomato was 4,897kg/10a in the improved arch type and the total leaf areas which related to photosynthesis was the largest in the saw - tooth type. 5. The improved arch type was proved to be proper to raise yield potential. The effect of the underground environment treatment on the quality and quantity of vegetable showed to be outstanding in the saw- tooth type with the evaporative cooling + improved drainage, and in the improved and conventional arch type with the trickle improved drainage. 6. In conclusion, the saw - tooth type and the improved arch type were proved to be labour saving rain shelters and the indoor environments in both types were better than that in the conventional arch type.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.10
• /
• pp.24-30
• /
• 2018

As the demand for underground space increases, many researchers have been studying the load reduction method using high compressible materials to solve for the stability problem of the overhead load and for the increase of the earth pressure which decreases the function of the underground structure. This paper determines the optimum soft zone and the effect of the using EPS Geofoam as a load reduction material to arch structures. A finite element analysis program, ABAQUS, is used to analyze the soil-structure interaction and the behavior of buried arch structures considering different four EPS Geofoam forms to confirm the most conservative shape. The optimum cross-sectional shape was determined by comparing the results of earth pressure reduction rate in accordance with the change of span-rise ratio and span length of the arch structure. It was confirmed that the earth pressure generated in the arch structure using the optimal soft zone selected by the numerical analysis was reduced by an average of 78%. In this study, the effect of EPS Geofoam on soil pressure reduction and its applicability to underground arch structures will provide an economical and conservative way to design underground structures and will help to increase the usability of deep underground space.

• Korean Journal of Applied Biomechanics
• /
• v.27 no.3
• /
• pp.229-238
• /
• 2017

Objective: The purpose of this study was to identify the effects of taping therapy and inner arch support on pes planus lower extremity alignment and gait. Method: The study was conducted on 13 women in their 20s who had pes planus and no gait problems. Independent variables were the condition of wearing basic socks (S1) and the condition of wearing socks with taping therapy and inner arch support (S2). The dependent variables were resting calcaneal stance position (RCSP), plantar pressure distribution during gait, and underlying and medial longitudinal arch angle measured using radiography. Statistical analysis was performed using the Wilcoxon test with SPSS 23.0 for comparison of S1 and S2. Results: In the RCSP measurement, the angle range of S2 changed to normal. Meary's angle appeared to be less than the angle of S1, indicating alleviation of the degree of pes planus. The calcaneal pitch angle increased at S2 from that at S1. The plantar pressure distribution was divided into four areas (toe, forefoot, midfoot, and hindfoot). At S2, the maximum pressure increased in the toe and midfoot. The maximum force increased significantly in the toe and midfoot but decreased significantly in the forefoot and hindfoot. In addition, the contact area increased overall especially at the midfoot and hindfoot. Contact time decreased in the toe and forefoot, but increased in the midfoot and hindfoot. Conclusion: Taping therapy and inner arch support showed structural improvement of the pes planus. In addition, the force and pressure applied to the foot during walking are distributed evenly in the area of the sole, thus positively affecting walking.

• The Journal of Korean Academy of Prosthodontics
• /
• v.32 no.4
• /
• pp.565-572
• /
• 1994

According to the classification of dental arch form and the analysis of patterns of chewing movement, the patterns of chewing movement in each group were evaluated and compared with those of the normal group. Results were summarized as follows ; 1. Opening phase in chewing movement In the group which the maxillary second molar positionsbuccal side, the chewing patterns which have the Vertical Guide Openings in frontal plane, the Posterior Guide Openings in hjorizontal plane were observed. In the group which the maxillary premolars position lingual side, the chewing paterns which have the Protrusive Shift Openings in horizontal plane and sagittal plane were observed. 2. Closing phase in chewing movement. In each group except for the normal group, the chewing patterns which have the Concave Closure in frontal plane and in Horizontal plane were observed. In the group which the maxillary premolars position buccal side, the chewing patterns which have the Lateral Guide Closure in frontal plane and in horizontal plane, the Vertical Guide Closre in sagittal plane were observed: From the results, as the characteristics of the dental arch form have appeared in chewing movement, the close relationships were found between dental arch form and chewing movement. It is suggested that the evaluation of dental arch form is effective in the diagnosis of function of stomatognathic system.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.29 no.1
• /
• pp.25-31
• /
• 2023

Background: In this study, the abductor hallucis activity and medial longitudinal arch angle were compared by performing four exercises, namely the short foot exercise, the short foot exercise with 2^nd~5^th toe extension, the short foot exercise with 2^nd~5^th toe extension with a load of 1kt on the sole, and the short foot exercise with 2^nd~5^th toe extension with a load of 2kg on the sole. Methods: Four short foot exercises as described above were performed by 20 healthy adult males and females. The abductor hallucis activity and medial longitudinal arch angle were measured and analyzed by surface electromyography and the Kinovea software program. Results: The short foot exercise with 2^nd~5^th toe extension, short foot exercise with 2^nd~5^th toe extension with a load of 1kg on the sole, and the short foot exercise with 2^nd~5^th toe extension with a load of 2kg on the sole showed significantly higher abductor hallucis activity than the short foot exercise alone. Among these, the short foot exercise with the 2^nd~5^th toe extension was the most effective. All exercises showed a significantly decreased medial longitudinal arch angle post-exercise than pre-exercise, and the short foot exercise with the 2^nd~5^th toe extension showed a significantly decreased medial longitudinal arch angle compared to the other three exercises. Conclusion: It is believed that the short foot exercise with the 2^nd~5^th toe extension can be proposed as an effective exercise that can replace the short foot exercise alone.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2001.10a
• /
• pp.267-270
• /
• 2001

It is difficult to install a ventilation window on the roof of single span greenhouse of arch shape. Investigation on the roof ventilation structure for those greenhouses was conducted. The effect of roof ventilation was evaluated by comparative experiments between greenhouse installing roof vent and having controlled side vent only. And ventilation efficiency was analyzed by experiments on the opening and closing operation of the roof and side vent.