• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.149-156
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• 1993

Precast concrete (P.C.) large panel structures have usually weaker stiffness at joints than that of monolithic in-situ reinforced concrete structures. But structural designers do not in general take into account this characteristics of P. C. large panel structures and use the same analytical models as for the monolithic structure. Therefore, the results of analysis obtained by using these models may be quite different from those actually occuring in real P.C. structure. In this study, the change in force and stress distribution and deflections of structure caused by applying lower shear stiffness at vertical joints are investigated through trying several finite element modeling schemes specific for P.C. structures. Finally, for engineers in practice. a simplified model, which takes account of the effect of lower shear stiffness at vertical joints, is proposed with the understanding on possible amount of errors.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.228-233
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• 2002

TWB(Tailor Welded Blanks) is one of the recent techniques to reduce the weight and cost of the body members. To apply the TWB technique, we must decide the position of the welding line and the thickness of the welded blanks. Although many researchers have tried to check the formability of welded blanks, there are not so many researches from the structural point of view. In this paper, the TWB technique is applied to combine the door inner panel and the hinge face panel into one piece. The finite element structural analysis of the door assembly leads to the final design of the tailor welded door inner panel, which shows the mass reduction of 1.08kg without the sacrifice of the structural stiffness. The structural stiffness analysis includes the frame stiffness analysis, the belt line stiffness analysis, the door sagging analysis and the vibration analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.6
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• pp.971-980
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• 1997

This study is to investigate the stiffness degradation of a composite laminated panel including transverse matrix cracks subjected to bending and twisting moments. Micromechanics theory on the composite material is derived by introducing crack density. Iterative numerical scheme is developed to calculate the degraded composite stiffness which has nonlinear relation due to the crack density. The finite element method is used for structural analysis of the composite panel. Structural responses of the composite panel are examined for various laminated angles and crack density under the bending and twisting moments. Also, the effect of crack opening and closing is considered in the examination. It is realized that the matrix cracks may cause severe stiffness reduction and should be considered in the composite laminated panel.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.116-118
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• 2014

A shape optimization problem is formulated to optimally design aluminum sandwich panel, which is used for high speed railway vehicle. An aluminum volume used in the panel is selected as a design objective with constraints on the stiffness and the transmission loss value. The formulated shape optimization problem is solved for a well -selected initial shape. The stiffness and transmission loss value of the obtained optimal shape are compared with those of the previously-reported panel.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.04a
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• pp.27-34
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• 1993

Precast large panel structures behave differently form frame and monolithic wall structures under external loads, because of the distinct planes of weakness in the horizontal and vertical joints between panels. These joints may slide and open during shaking, producing large localized changes in the bending and shear stiffness of individual walls. The structural behavior of large precast panel buildings depends on the relative strength and stiffness of the panels and joints. Special modeling are thus required for the analysis of precast panel connections. This study suggests a new analytical modeling and method to obtain the rational estimation of discontinuity and slip movements form the connections of precast large panel structures .

• Journal of Aerospace System Engineering
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• v.7 no.2
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• pp.1-7
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• 2013

Recently, there are a number of studies over dynamic analysis for minimizing vibration of flexible structures such as solar panel for agility of high-agility satellite. The traditional studies perform dynamic analysis of a solar panel assumed as rigid structure since the stiffness of solar panel is higher than the stiffness of solar panel's hinge spring. However, there are vibrations that have modes of bending and torsion when high-agility satellite rotate speedily. This vibrations result in delaying safety time of satellite or degrading image quality. This paper presents dynamic analysis's technique of satellites including the spring hinge of solar panel and flexible structural solar panel's effects described as the linear equation of motion using Lagrange's theorem, and verifies the validity of an established dynamic analysis's technique of satellites by comparing the finite element method. In addition high-agility satellite's dynamic characteristics of a torque profile are analyzed from the established dynamic analysis's technique of satellites.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.116-123
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• 2009

The elastic properties of core affect mechanical properties and deformation behaviours of the lightweight sandwich panel. The objective of the present paper is to estimate experimentally Young's and shear moduli of a core in internally structured boned (ISB) panel with woven metal as inner structures using the deflection theory of sandwich beam considered core stiffness. Three points bending experiments were performed to obtain force-deflection curves of the designed ISB panel in each material direction. The elastic and shear moduli of the core in each material direction were estimated from slopes and intercepts of relationships between compliance per the span length and square of the span length, respectively. The results of the estimation showed that the fabric technology of the woven metal affects the variation of the elastic properties in the core. Through the comparison of shear moduli and force-deflection curves of the proposed method and those without considering the core stiffness, it was shown that the core stiffness should be considered to estimate properly the Young's and shear moduli of ISB panels. Finally, the contribution ratio of bending and shear deflections of ISB panels to the total deflection was quantitatively examined.

• Journal of Korean Society of Steel Construction
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• v.12 no.5 s.48
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• pp.487-494
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• 2000

This paper intends to propose design information with the result or comparing the deformation capacity with different panel stiffness specimens and estimating the plastic deformation capacity, toughness and strength of welded joint connection according to the different scallop types. The test results of the beam to column unit structure are as follow: the non-scalloped and the low stiffness panel specimen have more desirable result values than the scalloped and the high stiffness one in plastic deformation. Comparing the scallop types shows very unlikely tendency as follows, second cracking occurs at the very edge of scallop in the scalloped specimen otherwise cracking occurs bond area of welded beam flange in the non-scalloped one.

• Computational Structural Engineering
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• v.7 no.3
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• pp.105-113
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• 1994

Precast concrete(P.C.) large panel structures have usually weaker stiffness at joints than that of monolithic in-situ reinforced concrete structures. But structural designers do not in general take into account this characteristics of P.C. large panel structures and use the same analytical models as for the monolithic structure. Therefore, the results of analysis obtained by using these models may be quite different from those actually occurring in real P.C. structure. In this study, the change in force and stress distribution and deflections of structure caused by applying lower shear stiffness at vertical joints are investigated through trying several finite element modeling schemes specific for P.C. structures, Finally, for engineers in practice, a simplified model, which takes account of the effect of lower shear stiffness at vertical joints, is proposed with the understanding on possible amount of errors.

• Steel and Composite Structures
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• v.44 no.4
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• pp.519-529
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• 2022

Sandwich structures with the superior mechanical properties such as high stiffness and strength-to-weight ratio, good thermal insulation, and high energy absorption capacity are used today in aerospace, automotive, marine, and civil engineering industries. These structures are composed of moderately stiff, thin face sheets that withstand the majority of transverse and in-plane loads, separated by a thick, lightweight core that resists shear forces. In this research, the finite element technique is used to simulate a sandwich panel with a truss core under axial compressive stress using ABAQUS software. A review of past experimental studies shows that the bondline between the core and face sheets plays a vital role in the critical failure load. Therefore, this modeling analyzes the damage initiation modes and debonding between face sheet and core by cohesive surface contact with traction-separation model. According to the results obtained from the modeling, it can be observed that the adhesive stiffness has a significant influence on the critical failure load of the specimens. To achieve the full strength of the structure as a continuum, a lower limit is obtained for the adhesive stiffness. By providing this limit stiffness between the core and the panel face sheets, sudden failure of the structure can be prevented.