• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.138-143
• /
• 2007

The leading-cab (high energy absorption area) of rolling stock directly is impacted on the frontal crash unlike other cabs. Thus, leading-cab has a structurally complex shape to solve getting concentrated loads. However, in order to enhance structural performance and to achieve the weight reduction of cab, changing the sizes and adjusting the distance of members do not take an effective result. Therefore, in design phase, to find the material arrangement which helps structural capacity be better should be done. This research applies the topology optimization to concept design of protective shell frame on strategy of crush energy absorption with considering pressure and vertical loads acting on the principal part of leading-cab. In this research, topology optimization method focuses on structural design, and which yields optimal material arrangement under given loads and boundary conditions using density method which has the density of material as design variables. Finally, this research presents optimal material arrangement and structure of protective shell frame on given loads with applying topology optimization.

• Steel and Composite Structures
• /
• v.26 no.5
• /
• pp.549-556
• /
• 2018

Progressive building collapse occurs when failure of a structural component leads to the failure and collapse of surrounding members, possibly promoting additional failure. Global system collapse will occur if the damaged system is unable to reach a new static equilibrium configuration. The most common type of primary failure which led to the progressive collapse phenomenon, is the sudden removal of a column by various factors. In this study, a method is proposed to prevent progressive collapse phenomena in structures subjected to removal of a single column. A vierendeel peripheral frame at roof level is used to redistribute the removed column's load on other columns of the structure. For analysis, quasi-static approach is used which considers various load combinations. This method, while economically affordable is easily applicable (also for new structures as well as for existing structures and without causing damage to their architectural requirements). Special emphasis is focused on the evolution of vertical displacements of column removal point. Even though additional stresses and displacements are experienced by removal of a structural load bearing column, the proposed method considerably reduces the displacement at the mentioned point and prevents the collapse of the structural frame.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.9
• /
• pp.733-738
• /
• 2011

A novel design of a simple square-frame USM (ultrasonic motor) was proposed. The stator of the motor consists of a square-frame shape elastic body and four rectangular plate ceramics. The four ceramics were attached to inner surfaces of the square frame elastic body. The same phase voltages were applied to the ceramics on horizontal surfaces, and 90 degree phase difference voltage were applied to the ceramics on vertical surfaces. To find a model that generates elliptical motion at outside of the stator, the finite element analysis program ATILA was used. The analyzed results were compared to the experimental results. As result, the model EL10EH3ET0.5CL4 which generates the maximum elliptical displacement was chosen by analyzing the resonance mode according to changes in frequency.

• Structural Engineering and Mechanics
• /
• v.77 no.3
• /
• pp.383-394
• /
• 2021

Column foot in traditional Chinese timber structures may be subjected to be uplifted due to the lateral load and subsequently reset under the vertical loads. The residual moment of the rocking column foot is the most important parameter representing the mechanical behaviors of column foot, and the simplification of joints is the basis of structural analysis of whole structure. The complicated mechanical behaviors of joint and the modeling of the column foot joint has been undertaken historically based on the experiments and numerical simulation. On the condition of limited application range of those models, a lack of simplified model to represent the mechanical behaviors of joint deserves attentions. There is a great need to undertake theoretical studies to derive the residual moment and make better simplified model of the joint. This paper proposes the residual moment and equivalent simplified model of the rotational stiffness for column foot joint. And, the timber frame is established based on the simplified model, which is verified by solid finite element model. Results show that a mutual agreement on the mechanical behaviors of the timber frame is obtained between the simplified model and the solid finite element model. This study can serve as the references of the structural analysis for the traditional timber structures.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.1
• /
• pp.69-78
• /
• 2023

For this purpose, the research is to study the architectural characteristic of SooMaJaiJeon which is one of the DongHwaSa in the traditional wooden architecture by dividing it into three section-bracket, roof structure and frame structure. This study is largely divided into four stage-section do subject, research and actual measurement and conclusion. The whole process was consistently executed through detailed steps. The com position of this study is as follows. The 1^st chapter-the purpose, background, method, object and range of the research. The 2^nd chapter-the history of SooMajaiJeon. the 3^rd chapter-the structure of Dapo-style bracket has generally considered, the frame structure of Dapo-style, vertical and horizontal member and podium, the characteristic of bracket with member and the structure, design of bracket, roof structure. In the 4^th chapter, the conclusion of this study has been summarized, Dapo-style is the building that has deep symbolism and structural characteristic of traditional wooden architecture. The frame structure has a dominant regional characteristic and a typical part of typological classification in SooMaJaiJeon.

• Nuclear Engineering and Technology
• /
• v.54 no.11
• /
• pp.4125-4133
• /
• 2022

KAERI (Korea Atomic Energy Research Institute) developed the conceptual design of PGSFR (Prototype Gen-IV Sodium Cooled Fast Reactor) and Burner Reactor. Since the reactor characteristics of the PGSFR and Burner Reactor are different, the shape, size and the arrangement of the main components in the reactors must be different. Therefore, the conceptual design for the fuel handling and transfer systems needs to be performed coinciding with the structure of the reactor. Especially, because a redan structure dividing hot and cold pool is installed in the reactor vessel, the conceptual design of the fuel handling and transfer system largely changes depending on the location of the redan structure. Various elements of the conceptual design and an integral arrangement for the fuel handling and transfer system were arranged according to the characteristics, sizes and shapes of the reactors. In this paper, the conceptual designs of the fuel handling and transfer system for PGSFR and Burner Reactor are described. Especially, an A-frame method is selected as the fuel handling and transfer system for the Burner Reactor, considering the layout of the internal structure. The tilt angle, diameter and length of A-frame is determined and the strength evaluation of the A-frame is performed.

• International Journal of High-Rise Buildings
• /
• v.3 no.2
• /
• pp.99-106
• /
• 2014

This paper presents the determination of the structural system of the Changsha IFC T1 tower with 452 m in architectural height and 440.45 m in structural height. Sensitivity analyses are carried out by varying the location of belt trusses and outriggers. The enhancement of seismic capacity of the outer frame by reasonably adjusting the column size is confirmed based on parametric studies. The results from construction simulation including the non-load effect of structures demonstrate that the deformation of vertical members has little effect on the load-bearing capacity of belt trusses and outriggers. The elastoplastic time-history analysis shows that the overall structure under rare earthquake load remains in an elastic state. The influence of the frame shear ratio and frame overturning moment ratio on the proposed model and equivalent mega column model is investigated. It is found that the frame overturning moment ratio is more applicable for judging the resistance of the outer frame against lateral loads. Comparison is made on the variation of these two effects between a classical frame-core tube-outrigger structure and a structure with diagonal braces between super columns under rare earthquakes. The results indicate that plasticity development of the top core cube of the braced structure may be significantly improved.

• International Journal of High-Rise Buildings
• /
• v.10 no.4
• /
• pp.265-283
• /
• 2021

To ensure that fire induced collapse of a building is prevented it is important to understand the sequence of events that can lead to this event. In this paper, the initiation of collapse mechanisms of generic a multi-storey steel frame subjected to vertical and horizontal travelling fires are analysed computationally by tracking the formation of plastic hinges in the frame and generation of fire induced loads. Both uniform and travelling fires are considered. In total 58 different cases are analysed using finite element software LS-DYNA. For the frame examined with a simple and generic structural arrangement and higher applied fire protection to the columns, the results indicate that collapse mechanisms for singe floor and multiple floor fires can be each split into two main groups. For single floor fires (taking place in the upper floors of the frame (Group S1)), collapse is initiated by the pull-in of external columns when heated beams in end bays go into catenary action. For single floor fires occurring on the lower floors(Group S2), failure is initiated (i.e. ultimate strain of the material is exceeded) after the local beam collapse. Failure in both groups for single floor fires is governed by the generation of high loads due to restrained thermal expansion and the loss of material strength. For multiple floor fires with a low number of fire floors (1 to 3) - Group M1, failure is dominated by the loss of material strength and collapse is mainly initiated by the pull-in of external columns. For the cases with a larger number of fire floors (5 to 10) - Group M2, failure is dominated by thermal expansion and collapse is mainly initiated by swaying of the frame to the side of fire origin. The results show that for the investigated frame initiation of collapse mechanisms are affected by the fire type, the number of fire floors, and the location of the fire floor. The findings of this study could be of use to designers of buildings when developing fire protection strategies for steel framed buildings where the potential for a multifloor fire exists.

• Journal of Korean Association for Spatial Structures
• /
• v.9 no.1
• /
• pp.69-78
• /
• 2009

Recent earthquake, such as the Northridge(1994), the Kobe(1995) and the Izmit(1990) earthquakes, gave serious damage in various buildings and bridges by the vertical seismic component. Most of the seismic designs neglect the vertical seismic component for usual frame structures. The purpose of this study is to evaluate the effects of the vertical seismic component and to compare the axial force of columns and plastic rotation angle of the analytical models in these effects. The vertical seismic component produced a large increment of axial force in columns. And the vertical seismic component caused a significant increase of the damage in the columns. As analysis result, increase of axial force cause the damage of columns and give possibility of story collapse mechanism of the structure system. Therefore, area that near fault ground motion is expected may be consider the effect of vertical component of seismic ground motions.

• Transactions of the KSME C: Technology and Education
• /
• v.5 no.2
• /
• pp.89-95
• /
• 2017

LCD robot vertical frame lets a arm assembly with glass substrate move up and down, so it must have high stiffness and strength. We applied new manufacturing process by using design optimization process such as topology and size optimization in order to satisfy the request of high stiffness and light weight. The proposed model should be evaluated for endurance strength. Therefore fatigue assessment for weak point of aluminum welding area of vertical frame studied with hot spot stress approach. And the actual stress measuring from test was compared and evaluated with the dynamic stress calculated from multi-body dynamics considering flexible body.