• International Journal of Automotive Technology
• /
• v.8 no.3
• /
• pp.319-325
• /
• 2007

Preload of critical engine bolts affects the performance and durability of engines. In modern engines that pursue higher power outputs and which are of lighter weight, it becomes more difficult to select an optimal target preload in consideration of various factors such as the role and structural characteristics of joint members, joint load, and fatigue durability of bolts and joint members. A procedure to select the bolt preload using computer-aided engineering technology, especially the finite element method, has been developed. The procedure is illustrated with connecting-rod bolts for which an appropriate preload is known. The selection criteria of target preload and the finite element modeling technique for connecting-rod bolts are also explained.

• Steel and Composite Structures
• /
• v.33 no.6
• /
• pp.767-776
• /
• 2019

In this article, a simple and robust multi-objective assessment method to control design angles and node positions connected among steel outrigger truss members is proposed to approve both structural safety and economical cost. For given outrigger member layouts, the present method utilizes general-purpose prototypes of outrigger members, having resistance to withstand lateral load effects directly applied to tall buildings, which conform to variable connecting node and design space deposition. Outrigger layouts are set into several initial design conditions of height to width of an arbitrary given design space, i.e., variable design space. And then they are assessed in terms of a proposed multi-objective function optimizing both minimal total displacement and material quantity subjected to design impact factor indicating the importance of objectives. To evaluate the proposed multi-objective function, an analysis model uses a modified Maxwell-Mohr method, and an optimization model is defined by a ground structure assuming arbitrary discrete straight members. It provides a new robust assessment model from a local design point of view, as it may produce specific optimal prototypes of outrigger layouts corresponding to arbitrary height and width ratio of design space. Numerical examples verify the validity and robustness of the present assessment method for controlling prototypes of outrigger truss members considering a multi-objective optimization achieving structural safety and material cost.

• Journal of Korean Association for Spatial Structures
• /
• v.16 no.2
• /
• pp.89-96
• /
• 2016

Cable structures are lightweight structures of flexible type, cable members have only axial stiffness related to tension, they can carry neither bending nor compression. This study is the analysis of cable truss systems are composed of upper and low cables by connecting bracing cables, the structural principle is based on a tensegrity system by using bracing tension members, discontinuous compression members and continuous tension members. A hanging roof of cable truss system is too flexible against vertical loads, most cable members are stabilized by connecting the prestressed upper and lower cable by bracing cables. A cable truss roof system is formed by adding a set of cables with reverse curvature to the suspension cables. With the sets of cables having opposite curvature to each other, cable truss is able to carry vertical load in both upward and downward direction with equal effectiveness, and then a cable truss acts as load bearing elements by the assemble of ridge cables, valley cables and bracing cables. This paper will be shown the geometric non-linear analysis result of cable truss systems with various sag ratio for deflections and tensile forces, the analytical results are compared with the results of other researchers.

• Journal of Korean Association for Spatial Structures
• /
• v.14 no.4
• /
• pp.55-64
• /
• 2014

In this study, Intersecting Tensegrity System that is integrated solid compression members with tension members was presented. This system is set up by connecting upper and lower compression members of pyramid shape with exterior tension members. In this system, the solid compression members are intersected each other and connected by a tension member in the center. This system is a variation of Tensegrity system, has a improved feature that the system is able to induce prestresses in all of tension members easily by adjusting the distance of a tension member in the center. The proposed system was studied by modeling, and the structural behavior of the system was investigated by mechanical analysis of the model. Furthermore, the features of the structural behavior variations was investigated when the composition elements(total height, size of surface, intersection length, etc.) are changed variously. It was also showed that the system is able to be used as a temporary space structure system with a membrane roof of inverse conical shape.

• Journal of the Korean Society of Safety
• /
• v.32 no.3
• /
• pp.60-65
• /
• 2017

This study examined the effect of rotational stiffness of joints between vertical and horizontal members in system supports. In order to prevent repeated disasters of system supports, it is important to examine the accurate behavior of system supports. Among various factors affecting the complex behavior of system supports, this study focused on the stiffness of joints between vertical and horizontal members. The considered joint was modelled by a rotational spring, but the translational displacements were fixed. The stiffness of rotational spring was calculated by utilizing the usable experimental data. In addition, the hinge connection condition, which is generally considered in design and only restrict the translational displacements, was modelled to compare the results. The case with the rotational stiffness in joints showed 3.5 times buckling loads compared to the case without the rotational stiffness. Thus, the structural behavior of the vertical member in system supports was similar to the vertical member with the fixed condition. For the combined stresses of vertical members, the combined stress ratios were reduced 5~6% by considering the rotational stiffness of connecting parts. However, for the horizontal member where showed relatively small stress range, the stresses were increased 2.3~7.6 times by considering the rotational stiffness in connecting parts.

• Journal of Korean Society of Steel Construction
• /
• v.15 no.3
• /
• pp.281-290
• /
• 2003

A series of connection tests of portal frames which were composed of cold-formed steel studs and rafters was carried out to study the moment-rotation relation, the rotational rigidity, and the yield and the ultimate moment of the connections. The main factors of the tests were the thickness, the shape of the connecting members which were made of mild steel, and the torsional restraints of the test specimens. The test results were compared with those obtained through the non-linear analysis, for verification. The secant stiffness estimated from the experimental moment-rotation curve was proposed for the rotational rigidity of semi-rigid connections, and its validity was verified in the structural frame analysis.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.1A
• /
• pp.147-154
• /
• 2008

The purpose of this study is to critically evaluate the structural performance of an innovative new shear resistance connecting structure of precast member. Joints such as shear resistance connecting structure require special attention when designing and constructing precast segmental structures. An experimental and analytical study was conducted to quantify performance measures and examine one aspect of detailing for developed shear resistance connecting structure. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. A joint element is used to predict the inelastic behavior of the joints between segmental members. Future work by the authors will do a model test of precast segmental prestressed concrete bridge columns with this shear resistance connecting structure, and examined both the structural behavior and seismic performance.

• Journal of the Korean Society for Railway
• /
• v.20 no.2
• /
• pp.257-264
• /
• 2017

The PC (Precast Concrete) construction method is a technique where concrete members that have been produced in a plant are constructed on site. Thus, continuity and secure integration of a structure that can be obtained by connecting rebars at splicing joint for PC members are the main areas of concern for this method. To evaluate the splicing and bonding performance according to application of a splice sleeve for connecting rebar in this research study, the diameter of rebar, development length, grouting strength etc. were set as variables. The performance and stiffness of splicing according to the development length of grout strength were measured and evaluated. In addition, by conducting comparative analysis on each of the variables, the factors that affected the splice sleeve for connecting rebar were discussed. The results confirmed that the strength and stiffness of the splice sleeve for connecting rebar were significantly affected by the development length while the increase in performance according to grout strength was not as significant.

• Journal of Korean Society of Steel Construction
• /
• v.15 no.5 s.66
• /
• pp.519-529
• /
• 2003

In recent years, the use of cold-formed steel roof truss has been increased in the steel houses and high-rise apartments. The design of the roof truss anchor connections has been based on the experience and decision of designers. In this paper, the structural behavior of anchor connections based on experimental and decision is described. In the tests, truss members and connection members were jointed directly with self-drilling screw fasteners and the simple shaped connection member with excellent workability and structural capacity was used to connect roof truss and sub-structure. The connecting method was selected according to the construction material of sub-structure: chemical anchor for reinforced concrete structure and welding or DX-Pin for steel structures. The pull-out tests of various type anchor connection were executed to obtain the strength and the stiffness and the result have been compared with AISI(1996) and AlSC(1989) specifications, Simple formulas for the shear strength of screw connections have been propose and compared with tests.

• Korean Institute of Interior Design Journal
• /
• v.19 no.5
• /
• pp.130-139
• /
• 2010

The urban style compact apartment which appeared at the end of 1990's was developed by the decrement of household members and in compliance with a new life style. Now it has its own market as a new trend. The purpose of this study is to better understand the characteristics of urban style compact apartments based on an analysis of apartments actually sold on 2008, in order to reflect on the future directions and developments. To support a comprehensive analysis, this study considered three types of compact apartments developed by : a. major developers which own multiple well-recognized brand names, b. mid-size developers under general brand names, c. new or small-size developers specializing in compact apartments. The results from 21 urban style compact apartments could be summarized as follow; 1. Most buyers are Singles or DINKs. The single women occupy a large percentage. 2. Condition of good location is under 5 minutes walk to station and accessibility to 2 and more station. 3. Exterior of building should be harmonious to surrounding and simple, the atmosphere of entrance hall should be warm and relaxed. 4. The spatial character of unit plans are developed by the ways of connecting spaces; 1) Connecting spaces by mobile partition: flexible spaces with expansion 2) Connecting spaces by hall: well arranged spaces with excursion and extends 5. The equipments of kitchen and security are fully carefully planned.