• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1999.04a
• /
• pp.102-109
• /
• 1999

Two phase simulated annealing algorithm is presented as a structural optimization technique and applied to minimum weight design of space trusses subjected to stress and displacement constraints under multiple loading conditions. Univariate searching algorithm is adopted for automatic selection of initial values of design variables for SA algorithm. The proper values of cooling factors and reasonable stopping criteria for optimum design of space truss structures are proposed to enhance the performance of optimization process. Optimum weights and design solutions are presented for two well-blown example structures and compared with those reported in the literature.

• Journal of Korean Association for Spatial Structures
• /
• v.12 no.2
• /
• pp.89-98
• /
• 2012

This study investigates the optimum structural design of space truss considering global buckling, and is to obtain the minimal weight of the structure. The mathematical programming method is used for optimization of each member by member force. Besides, dynamic programming method is adapted for consideration in snap-through buckling. The mathematical modeling for optimum design of truss members consists of objective function of total weight and constrain equations of allowable tensile (or compressive) stress and slenderness. The tangential stiffness matrix is examined to find the critical point on equilibrium path, and a ratio of the buckling load to design load is reflected in iteration procedures of dynamic programming method to adjust the stiffness of space truss. The star dome is examined to verify the proposed optimum design processor. The numerical results of the model are conversed well and satisfied all constrains. This processor is a relatively simple method to carry out optimum design with consideration in global buckling, and is viable in practice with respect to structural design.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.630-633
• /
• 2003

In domestic construction industry, now demand for airport facilities, gymnastic facilities, mass meeting facilities, sales facilities is increasing. Because of this, demand for huge space is also increasing. In making huge space, existing PEB(Pre-Engineered Building) and Pipe Truss, As span is lager and larger, steel weight is increasing and hard to apply for large span. For solving this problem, Many program was proposed, and in that Space Frame was rising. But in domestic construction there are very rare practical use for Space Frame. In this study, we wish to introduce Space Frame that has several advantages in construction expense, construction time, constructibility and also with analyzing example for applying Space Frame, wish to investigate characteristic of Space Frame. Go forward better, through comparison of other different old method and basic character of Space Frame, confirm advantage of Space Frame that have infinite development possibility and revitalize the Space Frame in domestic study and further more wish to raise practical use for Space Frame.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.10 s.181
• /
• pp.2502-2512
• /
• 2000

Truss structures are widely used in many space structures, such as large antenna systems, space stations, precision segmented telescopes because they are light in weight and amenable in assembly or deployment. But, due to the low damping capacity, they remain excited for a long time once disturbed. These structural vibrations can reduce life of the structures and cause unstable dynamic characteristics. In this research, vibration suppression experiment has carried out with a three-dimensional 15-member truss structure using two piezoelectric actuators. Piezoelectric actuators which consist of stacks of thin piezoelectric material disks are directly inserted to the truss structure collocated with the strain sensors. Each actuator is controlled digitally in decentralized manner, based on local integral and proportional feedback. The optimal positions of the actuators are determined by the modal damping ratio and the control force. Numerical simulation has carried out to determine optimal position of each actuator.

• Journal of Ocean Engineering and Technology
• /
• v.17 no.6
• /
• pp.53-57
• /
• 2003

Optimum design of most structural system requires that design variables are regarded as discrete quantities. This paper presents the use of Genetic Algorithm for determining the optimum design for truss with discrete variables. Genetic Algorithm are know as heuristic search algorithms, and are effective global search methods for discrete optimization. In this paper, Elitism and the method of conferring penalty parameters in the design variables, in order to achieve improved fitness in the reproduction process, is used in the Genetic Algorithm. A 10-Bar plane truss and a 25-Bar space truss are used for discrete optimization. These structures are designed for stress and displacement constraints, but buckling is not considered. In particular, we obtain continuous solution using Genetic Algorithms for a 10-bar truss, compared with other results. The effectiveness of Genetic Algorithms for global optimization is demonstrated through two truss examples.

• Structural Engineering and Mechanics
• /
• v.9 no.2
• /
• pp.111-126
• /
• 2000

Truss type structures are attractive to a variety of engineering applications on earth as well as in space due to their high stiffness to mass ratios and ease of construction and fabrication. During the service life, an individual member of a truss structure may lose load carrying capacity due to many reasons, which may lead to collapse of the structure. An analytical and computational procedure has been developed to study the response of truss structures subject to member failure under static and dynamic loadings. Emphasis is given to the dynamic effects of member failure and the propagation of local damage to other parts of the structure. The methodology developed is based on nonlinear finite element analysis technique and considers elasto-plastic material nonlinearity, postbuckling of members, and large deformation geometric nonlinearity. The pseudo force approach is used to represent the member failure. Results obtained for a planar nine-bay indeterminate truss undergoing sequential member failure show that failure of one member can initiate failure of several members in the structure.

• Journal of Korean Association for Spatial Structures
• /
• v.22 no.3
• /
• pp.15-24
• /
• 2022

In this research, the case of modern wooden structures since 1950 with span of 30m or more was investigated and analyzed the construction status and structural planning characteristics of wooden large space architecture. As a result, wooden large space buildings have built around Asia, North America, and Europe, in which cases of ice skating stadiums with span of 30m to 60m were concentrated. In the case of baseball parks and football stadiums, even a span of about 165m was built in a wooden structure. In addition, it was found that the structural systems used in wooden large space structures were a funicular arch and truss structure, in that cases, funicular arch system consisting of radial arrangements was used in the examples exceeded 150m and the two way truss system was also used in long span wooden structures exceeding 100m. As the truss structure with a tie-rod or the flexure+tension structure was partially investigated, it can be seen that various timber structural systems need to be devised and researched. Also, It was investigated that a technique in which some members of the truss are made of steel or a composite member of steel and timber is also possible to develop

• Journal of Korean Society of Steel Construction
• /
• v.24 no.3
• /
• pp.289-299
• /
• 2012

The goal of this paper is to apply the multi-step Taylor method to a space truss, a non-linear discrete dynamic system, and analyze the non-linear dynamic response and unstable behavior of the structures. The accurate solution based on an analytical approach is needed to deal with the inverse problem, or the dynamic instability of a space truss, because the governing equation has geometrical non-linearity. Therefore, the governing motion equations of the space truss were formulated by considering non-linearity, where an accurate analytical solution could be obtained using the Taylor method. To verify the accuracy of the applied method, an SDOF model was adopted, and the analysis using the Taylor method was compared with the result of the 4th order Runge-Kutta method. Moreover, the dynamic instability and buckling characteristics of the adopted model under step excitation was investigated. The result of the comparison between the two methods of analysis was well matched, and the investigation shows that the dynamic response and the attractors in the phase space can also delineate dynamic snapping under step excitation, and damping affects the displacement of the truss. The analysis shows that dynamic buckling occurs at approximately 77% and 83% of the static buckling in the undamped and damped systems, respectively.

• Journal of Korean Association for Spatial Structures
• /
• v.13 no.2
• /
• pp.47-55
• /
• 2013

The design composition elements and the mechanical behavior of trusses have been investigated for Pratt trusses. As a result, it was determined that the design composition elements of the trusses consist of the composition of webs, the distance between joints, the chords profile, the depth of the truss, and the double chord composition. In addition, by analyzing models with a variation of elements, comprehensive features of structural behavior have been presented for variations of design of Pratt trusses. This is to provide more effective and useful design information on truss structure in the architectural and structural planning stage.

• International Journal of Aeronautical and Space Sciences
• /
• v.18 no.4
• /
• pp.651-661
• /
• 2017

A truss-braced wing (TBW) aircraft has recently received increasing attention due to higher aerodynamic efficiency compared to conventional cantilever wing aircraft. For conceptual TBW aircraft design, we developed a propulsion-and-airframe integrated design environment by replacing a semi-empirical turbofan engine model with a thermodynamic cycle-based one built upon the numerical propulsion system simulation (NPSS). The constructed NPSS model benefitted TBW aircraft design study, as it could handle engine installation effects influencing engine fuel efficiency. The NPSS model also contributed to broadening TBW aircraft design space, for it provided turbofan engine design variables involving a technology factor reflecting progress in propulsion technology. To effectively consolidate the NPSS propulsion model with the TBW airframe model, we devised a rapid, approximate substitute of the NPSS model by reduced-order modeling (ROM) to resolve difficulties in model integration. In addition, we formed an artificial neural network (ANN) that associates engine component attributes evaluated by object-oriented weight analysis of turbine engine (WATE++) with engine design variables to determine engine weight and size, both of which bring together the propulsion and airframe system models. Through propulsion-andairframe design space exploration, we optimized TBW aircraft design for fuel saving and revealed that a simple engine model neglecting engine installation effects may overestimate TBW aircraft performance.