• Structural Engineering and Mechanics
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• v.31 no.3
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• pp.297-314
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• 2009

When the temperature of a structure varies, there is a tendency to produce changes in the shape of the structure. The resulting actions may be of considerable importance in the analysis of the structures having non-prismatic members. Therefore, this study aimed to investigate the modeling, analysis and behavior of the non-prismatic members subjected to temperature changes with the aid of finite element modeling. The fixed-end moments and fixed-end forces of such members due to temperature changes were computed through a comprehensive parametric study. It was demonstrated that the conventional methods using frame elements can lead to significant errors, and the deviations can reach to unacceptable levels for these types of structures. The design formulas and the dimensionless design coefficients were proposed based on a comprehensive parametric study using two-dimensional plane-stress finite element models. The fixed-end actions of the non-prismatic members having parabolic and straight haunches due to temperature changes can be determined using the proposed approach without necessitating a detailed finite element model solution. Additionally, the robust results of the finite element analyses allowed examining the sources and magnitudes of the errors in the conventional analysis.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.853-855
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• 2003

Microphytobenthos that supply nutrients to the intertidal ecosystem play an important part as a primary producer. If we estimate distribution and density of microphytobenthos, we can possibly calculate a volume of primary product in the tidal flat and its effect to the intertidal ecosystem. To estimate the portion of microphytobenthos, we used a linear spectral unmixing (LSU) method. LSU is a tool for inference the proportions of the pure components (or end-members) in a mixed pixel. The selection of end-members is critical to LSU. The end-members can be selected either from spectral libraries built from field surveys or from a remotely sensed image. We compared the two approaches of end-member selection, and the preliminary results showed end-members from from spectral library are as effective as those from image itself.

• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.1-7
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• 2003

The front-end side members of vehicles(spot welded hat and double hat shaped section members) absorb most of the impact energy in a case of front-end collision. In this paper, specimens with various spot weld pitches have been tested with a high impact velocity of 7.19m/sec(impact energy of 1034J). The axial impact collapse simulation on the sections has been carried out to review the collapse characteristics of these sections, using an explicit finite element code, LS-DYNA3D. Comparing the results with experiments, the simulation has been verified; the energy absorbing capacity is analyzed and an analysis method is suggested to obtain exact collapse loads and deformation collapse modes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1549-1552
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• 2003

The front-end side members of automobiles absorb most of the energy in a front-end collision. The front-end side members are required to have a high stiffness together with easiness to collapse sequentially to absorb more impact energy. The axial static collapse test (5mm/mim) was conducted by using UTM with respect to the single hat shaped section members which are the standard section shape of the spot welded section members, to the single cap shaped section members, to the double cap shaped section members and to the double hat shaped section members whose section shape are changed in order to give more stiffness. As a result of test, the energy absorbing characteristic was analyzed for different section shapes. That is, it was analyzed that the change of section shape influenced the absorbing energy, the mean collapse load and the maximum collapse load, and that the relation between the change of section shape and the collapse mode.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.177-182
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• 2003

The front-end side members of automobiles absorb most of the energy in a case of front-end collision. The front-end side members are required to have a high stiffness together with easiness to collapse sequentially to absorb more impact energy. The axial static collapse test (5mm/min) was conducted by using UTM for form different types of members which have different cross section shapes; single hat, single cap, double cap, and double hat. The single hat shaped section member has the typical standard section, which the double hat shape section has a symmetry in the center to have more stiffness. As a result of the test, the energy absorbing characteristic was analyzed for different section shapes. It turned out that the change of section shape influence the absorbing energy, the mean collapse load and the maximum collapse load, and the relation between the change of section shape and the collapse mode.

• Steel and Composite Structures
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• v.35 no.1
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• pp.29-41
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• 2020

Cross-beams of modern through truss bridges are connected to truss chord at its nodes and between them. It results in variable rotational end restraint for cross-beams, thus variable bending moment distribution. This feature is captured in three-dimensional modelling of through truss bridge structure. However, for preliminary design or rapid assessment of service load effects such technique of analysis may not be available. So an analytical method of assessment of rotational end restraint for cross-beam of through truss bridges was worked out. Two cases - nodal cross-beam and inter-nodal cross-beam - were analyzed. Flexural and torsional stiffness of truss members, flexural stiffness of deck members and axial stiffness of wind bracing members in the vicinity of the analyzed cross-beam were taken into account. The provision for reduced stiffness of the X-type wind bracing was made. Finally, general formula for assessment of rotational end restraint was given. Rotational end restraints for cross-beams of three railway through truss bridges were assessed basing on the analytical method and the finite element method (three-dimensional beam-element modelling). Results of both methods show good agreement. The analytical method is able to reflect effects of some structural irregularities. On the basis of the obtained results the general values of rotational end restraint for nodal and inter-nodal cross-beams of railway through truss bridges were suggested.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.102-107
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• 2000

The extensive use of pretensioned prestressed concrete in the modem construction industry, together with wider application of pretensioned components for structural purposes requires some important consideration on the adequate transfer of prestress force into the concrete, especially around the end zones of pretensioned member. The main objective of this paper is to study the effects of various important parameters on the bond characteristics of prestressing strand around the end zone of high strength pretensioned concrete members. To this end, a comprehensive experimental program has been set up. The principal test variables considered were strand diameter, concrete strength, concrete cover size. The present study provides valuable test data for the realistic and accurate determination of transfer length, which can be efficiently used for improving the design equation of transfer length in pretensioned prestressed concrete members.

• Journal of Hospice and Palliative Care
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• v.24 no.3
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• pp.194-197
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• 2021

End-of-life assessments aim to help dying patients and their families plan clinical interventions in advance and prepare them for a peaceful end of life, in which the patient accepts life and death, and the family accepts the patient's departure. It is important to assess whether death is imminent within a few days, because critical hospice care is provided intensively during that period. The following five changes constitute objective evidence of the end of life: diminished daily living performance, decreased food intake, changes in consciousness and increased sleep quantity, worsening of respiratory distress, and end-stage delirium. As subjective evidence, it is suggested that sensitive perceptions of experienced nurses and the feelings of family members caring for patients should also be considered. When notifying a patient or family members that the end of life is approaching, the members of the multidisciplinary hospice team must communicate with each other, share accurate information, and provide consistent explanations. They must also listen to non-verbal communication in an empathic and supportive manner.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.83-86
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• 2005

The front-end side members of automobiles, such as the hat-shaped section member, absorb most of the energy during the front-end collision. The side members absorb more energy in collision if they have higher strength and stiffness, and stable folding capacity (local buckling). Using the above characteristics on energy absorption, vehicle should be designed light-weight to improve fuel combustion ratio and reduce exhaust gas. Because of their specific strength and stiffness, CFRP are currently being considered for many structural (aerospace vehicle, automobiles, trains and ships) applications due to their potential for reducing structural weight. Although CFRP members exhibit collapse modes that are significantly different from the collapse modes of metallic materials, numerous studies have shown that CFRP members can be efficient energy absorbing materials. In this study, the CFRP side members were manufactured using a uni-directional prepreg sheet of carbon/Epoxy and axial static collapse tests were performed for the members. The collapse mode and the energy absorption capability of the members were analyzed under the static load.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.2
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• pp.23-29
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• 2003

The spot welded sections of automobiles (hat and double hat shaped sections) absorb most of the energy in a front-end collision. The target of this paper is to analyze the energy absorbing capacity of the structure against the front-end collision, and to obtain useful information for designing stage. Changed the spot welded pitches on the flanges, the hat and double hat shaped section members were tested on the axial collapse loads at various impact velocities. It was expected that para-closed sections would show collapse characteristics which be quite different from those of perfectly closed sections. Hat shaped section members were tested at the impact collapse velocities of 4.72m/sec, 6.54m/sec and 7.1m/sec and double hat shaped section members were tested at the impact collapse velocities of 6.54m/sec, 7.1 m/sec and 7.27m/sec.