• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.5
• /
• pp.603-608
• /
• 2010

In this study, one type of circular shaped composite tube was used, combined with reinforcing foam and without foam. Furthermore, CFRP(Carbon Fiber Reinforced Plastic) circular member manufactured from CFRP prepreg sheet for lightweight design. CFRP is an anisotropic material which is the most widely adapted lightweight structural member. The crashworthy behavior of circular composite material tubes subjected to static axial compression under same conditions is reported in this paper. Test was executed in order to compare the results to the energy absorption and collapse shape. The collapse mode during the failure process were observed and analyzed. The behavior of polymeric foams to the tubes crashworthiness were also investigated. According to the experimental results, specimens filled with foam are higher total energy absorption than the other specimens not filled with the foam.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.5 no.1
• /
• pp.1-8
• /
• 1999

During the last 10 years, the various type of high speed craft have been greatly developed, and since around of 1990 the large size of high speed passenger and/or cargo vessels are also introduced and took into the service in the various routes over the world. In a marine traffic way some bridge need to build across a rivers, cannals or a waterways. This one will be an obstruction and potential risk of collision in the way of high speed craft. Accordingly some of collision accident have been reported, which were caused by a lost control, wind and hydrodynamic forces, fog or human errors. In this paper a high speed craft having 40 m length is assumed to be collided with a circular type of bridge piers at right angle. The mode of deformation, penetration depth of collapse, impact forces, reduction of speed, loss of kinetic energy, and influence of scantlings, etc. have been calculated in each speed with a time variation to find a maximum values within a limit, and are graphically presented.

• Journal of Auto-vehicle Safety Association
• /
• v.6 no.2
• /
• pp.5-11
• /
• 2014

Front side member of the front impacted vehicle plays a key role in minimizing the impacting load transferred to the compartment. To perform that required function, axial collapse should be dominant during side member crashing and, prior to designing side member, it is crucial to minimize bending moment occurred at the front end. In this study, for FE model of a SUV front body, front impact analyses were carried to find out bumper stay design which effectively develope axial collapse in the side member. As a previous work, the thickness of side member reinforcement were changed. Next, the inner thickness of bumper stay was increased. Also, the bead shape and location were modified. Final front body model showed much more axial collapsed mode and enhanced crash performance. In addition, a stay of octagon section was adopted and that model exhibited distinctive increase in impact energy absorption.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.6
• /
• pp.892-896
• /
• 2012

CFRP composites with light weight, high strength, and high elasticity by comparing with metal are widely used rather than previous steel plates. However, CFRP composite material has the weakness at hydrothermal and collapsed impact environment. Especially, moisture absorption into composite material can change molecule arrangement and chemical properties under hydrothermal environment. And static collapse experiment is the research in the differences of absorbed energy and deformation mode between moisture and non-moisture absorbed specimens. This study is compared and analyzed on the progress change of moisture absorption ratio after setting up the temperatures of 60 and 80 degrees C in order to comprehend how the change in the temperature influences on moisture absorption status inside CFRP composite materials.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.2040-2045
• /
• 2008

The priority of Crashworthiness concept for rolling stock is progressively increasing to reduce the damage of drivers and passengers as well as the car. For the first step of this research, the analysis of the crash elements have been performed. Also the longitudinal collapse force and mode is important point for whole carbody structure to guarantee the lower force at end part rather than the main passenger area. The carbody quasi-static collapse analysis and real test has been performed in the research. The crash elements FEA and test has been performed as well. After the initial Analysis and test, the correlation analysis between the FEA and test has been performed by FEA tunning. All this result will be used for real crashworthiness design for carbody structure.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.36 no.6
• /
• pp.399-405
• /
• 2023

This study presents an optimal seismic design method based on genetic algorithms to induce beam-hinge collapse mechanisms in reinforced concrete moment frames. Two objective functions are used. The first minimizes the cost of the structure and the second maximizes the energy dissipation capacity of the structure. Constraints include strength conditions of columns and beams, minimum conditions for column-to-beam flexural strength ratio, and conditions for preventing plastic hinge occurrence of columns. Linear static analysis is performed to evaluate the strength of members, whereas nonlinear static analysis is carried out to evaluate energy dissipation capacity and occurrence of plastic hinges. The proposed method was applied to a four-story example structure, and it was confirmed that solutions for inducing a beam-hinge collapse mechanism are obtained. The value of the column-beam flexural strength ratio of the obtained design was found to be larger than the value suggested by existing seismic codes. A more robust strategy is needed to induce a beam-hinge collapse mode.

• Composites Research
• /
• v.20 no.3
• /
• pp.8-16
• /
• 2007

Bending collapse of light-weight square tubes used for vehicle structure components is a dominant failure mode in oblique collision and rollover of vehicles. In this paper bending performances of aluminum-GFRP hybrid tube beams were evaluated in relation with bending deformation behavior and energy absorption characteristics. Aluminum/GFRP hybrid tube beams fabricated by inserting adhesive film between prepreg and metal layer were used in the bending test. Failure mechanisms of hybrid tubes under a bending load were experimentally investigated to analyze the bending performance as a function of ply orientation and composite layer thickness. Ultimate bending moments and energy absorption capacity of hybrid tube beams were obtained from the measured load-displacement corves. It was found that aluminum/GFRP hybrid tubes could be converted to rather stable collapse mode showing excellent energy absorption capacity in comparison to the pure aluminum tube beams. In particular, the hybrid tube beam with $[0^{\circ}/90^{\circ}]s$ composite layer showed a large improvement by about 78% in energy absorption capacity and by 29% in specific energy absorption.

• Proceedings of the KIEE Conference
• /
• 1990.07a
• /
• pp.341-345
• /
• 1990

This paper presents the three section sliding mode control algorithm based on hysteresis current control add indirect field oriented control method, and applies it to the position control of induction motor. The three section sliding trajectories are defined in such a way that the system responds following a max acceleration line, then a max speed line, and finally a max deceleration line. This control scheme solves the problem of robustness loss during the reaching phase that occurs in conventional VSC strategy, and ensures the stable sliding mode and robustness enhancement throughout an entire response. Also, the PID controller operating in parallel is adopted to eliminate the sliding mode's collapse phenomenon near the origin caused by steady state chattering phenomenon Digital simulation results confirm that the dynamic performance of the system is insensitive to parameter variations and disturbances.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.6
• /
• pp.270-278
• /
• 1999

This paper describes the collapse characteristics of the rectangular tube under eccentric compressive load. Overall buckling stress and bifurcation criterion (slenderness ration)are investigated. modified secant formula(MSF) is proposed to decide overall buckling stress. The bifurcation criterion which can distinguish between the local and overall buckling mode shapes is suggest by equating the local and overall buckling stresses. Additionally the effect of initial imperfection on bifurcation criterion is investigated.

• Steel and Composite Structures
• /
• v.25 no.3
• /
• pp.327-335
• /
• 2017

To gain more knowledge of aluminum foam sandwich structure and promote the engineering application, aluminum foam sandwich consisting of 7050 matrix aluminum foam core and 304 stainless steel face-sheets was studied under three-point bending by WDW-T100 electronic universal tensile testing machine in this work. Results showed that when aluminum foam core was reinforced by 304 steel face-sheets, its load carrying capacity improved dramatically. The maximum load of AFS in three-point bending increased with the foam core density or face-sheet thickness monotonically. And also when foam core was reinforced by 304 steel panels, the energy absorption ability of foam came into play effectively. There was a clear plastic platform in the load-displacement curve of AFS in three-point bending. No crack of 304 steel happened in the present tests. Two collapse modes appeared, mode A comprised plastic hinge formation at the mid-span of the sandwich beam, with shear yielding of the core. Mode B consisted of plastic hinge formation both at mid-span and at the outer supports.