• Steel and Composite Structures
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• v.37 no.4
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• pp.405-418
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• 2020

The application of double-skin composite wall should meet different layout plans. However, most available research focused on the rectangular section with uniform axial compression. In this research, the structural behavior of double-skin composite wall with L section was studied. Due to the unsymmetric geometric characteristics, the considered loading condition combined the axial compression and biaxial bending. Five specimens were designed and tested under eccentric compression. The variables in the test included the width of the web wall, the truss spacing, the thickness of the steel faceplate, and the thickness of the web wall. The test results were discussed in terms of the load-displacement responses, buckling behavior, stiffness, ductility, strength utilization, strain distribution. Two modern codes were employed to predict the interaction between the axial compression and the biaxial bending. The method to calculate the available bending moment along the two directions was proposed. It was found that CECS 159:2004 offers more suitable results than AISC 360.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.8
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• pp.883-891
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• 2003

In this study, a change of hand of fabrics dyed with persimmon juice was measured using Kawabata Evaluation System. Using various cotton fabrics, linen fabric and silk fabric used frequently for persimmon juice dyeing, we examined the changes of physical properties and hand according to persimmon juice dyeing and washing. The dynamic characteristics of hand were measured tensile, shear, bending, compression, surface properties, thickness and weight. Linearity of load-extention and tensile resilience were increased in all kinds of fabrics after dyeing. Tensile energy decreased in cotton fabric 2(gauze), cotton fabric 3(muslin) and linen fabric. Shear stiffness and hysteresis of shear increased in most of fabrics. Bending rigidity of the bending property and hysteresis of bending, linearity of compression of the compression property, compression energy and compression resilience increased in all kinds of fabrics after dyeing. Thickness and weight increased much in all kinds of fabrics after dyeing. In the primary hand value, stiffness and anti-drape stiffness increased in all kind of fabrics after dyeing. The fullness and softness, crispness, scrooping feeling and flexibility with soft feeling decreased. As the stiffness after persimmons dyeing increased, it was suitable for clothes material of summer.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.12
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• pp.822-829
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• 2015

A transfer matrix method has been developed to determine the more accurate natural frequencies for the bending vibration of Bernoulli-Euler beam with linearly reduced width and a concentrated tip mass. The proposed method can be computed an infinite number of the natural frequencies using a single element. Using the differential equation, shear force, and bending moment in which can be deduced by the diverse variational principles, a transfer matrix is formulated. The roots of the differential equation are computed by the Frobenius method. The effect of the concentrated mass for the natural frequencies of width-tapered beams is examined through a parametric study, and to show the accuracy of the proposed method, the computed results compared with those obtained from commercial finite element analysis program(ANSYS).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.9
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• pp.957-962
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• 2009

Sialon was produced by hot-pressing the mixtures of $Si_3N_4$, AlN and $Y_2O_3$ powders. All fracture tests were performed on a three-point loading system with a 30 mm bending span. Fracture toughness and Vickers hardness of smooth specimen were average 7.05 $MPa{\cdot}m^{0.5}$ and Hv = 1580, respectively. Density of three kinds of specimens, smooth specimen, smooth and healed specimen, smooth with $SiO_2$ colloidal coating and healed specimen, had beyond 99 % of theoretical density. Bending strength of smooth healed specimens had high strength more than 1 GPa. Crack healed specimens recovered as strength as smooth specimen. That is, cracked specimen with $SiO_2$ colloidal coating on cracked part recovered strength by heat treatment, completely. Crack healing of $Si_3N_4$ composite ceramics had contributed glassy $SiO_2$ to strength recovery. Limiting high temperature for bending strength of heat treated smooth specimen for bending strength was about 1273 K.

• Structural Engineering and Mechanics
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• v.46 no.1
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• pp.39-51
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• 2013

An extremum method is presented to predict the wrinkling characteristics of the inflated cone in bending. The wrinkling factor is firstly defined so as to obtain the wrinkling condition. The initial wrinkling location is then determined by searching the maximum of the wrinkling factor. The critical wrinkling load is finally obtained by determining the ratio of the wrinkling moment versus the initial wrinkling location. The extremum method is proposed based on the assumption of membrane material of beam wall, and it is extended to consider beam wall with thin-shell material in the end. The nondimensional analyses show that the initial wrinkling location is closely related to the taper ratio. When the taper ratio is higher than the critical value, the initial wrinkles will be initiated at a different location. The nondimensional critical wrinkling load nonlinearly increases as the taper ratio increases firstly, and then linearly increases after the critical taper ratio. The critical taper ratio reflects the highest load-carrying efficiency of the inflated cone in bending, and it can be regarded as a measure to optimize the geometry of the inflated cone. The comparative analysis shows fairly good agreement between analytical and numerical results. Over the whole range of the comparison, the mean differences are lower than 3%. This gives confidence to use extremum method for bending-wrinkling analysis of inflated conical cantilever beam.

• Transactions of Materials Processing
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• v.27 no.3
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• pp.177-183
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• 2018

The influence of electric current on the springback characteristics of AZX311 magnesium alloy and martensitic steel after V-bending test is investigated. Various pulsed electric currents are applied into the specimens followed by a V-bending test, and the changes in the springback angle are measured. In order to evaluate not only the thermal effect but also the athermal effect of electric current on the springback angle, the temperature rises resulting from the applied electric current are measured for all test conditions. As a result, it was found that the springback is significantly decreased as the current density increases. As for the martensitic steel, since the dislocation recovery immoderately occurs at a high electric current density condition of $80A/mm^2$, the optimal current density condition should be required.

• Journal of the Korean Wood Science and Technology
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• v.25 no.2
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• pp.52-60
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• 1997

Hornbeam trees(Carpinus laxiflora BL.) are growing in Korea and have good characteristics such as relatively high density, fine texture, split- resistance, and white colour. However, they have seldom been used as manufacturing materials This study was carried out to evaluate the possibility of using hornbeam wood as bent, wood furniture materials. Softening methods were steaming and micro-wave heating. The specimens of $15{\times}15{\times}350mm$ were used green or air-dried, and were steamed at $100^{\circ}C$ for 20min, or microwave heat ed f or 60 seconds. The bending processing conditions are showed in Table 3. The minimum solid-bending radii of air-dried wood were 40mm for steaming and 200mm for micro-wave heating, respectively. And that of green wood were 40mm for micro-wave heating. In conclusion, both of the steamed wood and micro-wave heated green wood showed very good solid bending processing properties, but micro-wave heated air-dried wood were not sufficient for bent-wood furniture.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.3
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• pp.1-10
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• 1988

A higher order plate bending finite element using cubic in-plane displacement profiles is proposed for geometrically nonlinear analysis of thin and thick plates. The higher order plate bending element has been derived from the three dimensional plate-like continuum by discretization of the equations of motion by Galerkin weighted residual method, together with enforcing higher order plate assumptions. Total Lagrangian formulation has been used for geometrically nonlinear analysis of plates and consistent linearization by Newton-Raphson method has been performed to solve the nonlinear equations. The element characteristics have been computed by, selective reduced integration technique using Gauss quadrature to avoid shear locking phenomenon in case of extremely thin plates. Several numerical examples were solved with FEAP macro program to demonstrate versatility and accuracy of the present higher order plate bending element.

• Journal of the Korean Wood Science and Technology
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• v.11 no.2
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• pp.52-60
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• 1983

Hornbeam trees(Carpinus laxiflora BL.) are growing in Korea and have good characteristics such as relatively high density, fine texture, split-resistance, and white colour. However, they have seldom been used as manufacturing materials This study was carried out to evaluate the possibility of using hornbeam wood as bent-wood furniture materials. Softening methods were steaming and micro-wave heating. The specimens of $15{\times}15{\times}350mm$ were used green or air-dried, and were steamed at $100^{\circ}C$ for 20min, or microwave heated for 60 seconds. The bending processing conditions are showed in Table 3. The minimum solid-bending radii of air-dried wood were 40mm for steaming and 200mm for micro-wave heating, respectively. And that of green wood were 40mm for micro-wave heating. In conclusion, both of the steamed wood and micro-wave heated green wood showed very good solid bending processing properties, but micro-wave heated air-dried wood were not sufficient for bent-wood furniture.

• Computers and Concrete
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• v.26 no.1
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• pp.63-74
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• 2020

In this investigation, study of the bending response of functionally graded (FG) porous plates is presented using a cubic shear deformation theory. The properties of the FG-plate vary according to a power-law distribution which is modified to approximate material characteristics for considering the effect of porosities. The equilibrium equations are derived by using the principle of virtual work and solved by using Navier's procedure. Various numerical results are discussed to demonstrate the influence of the variation of the power index, the porosity parameter and the geometric ratios on the bending response of FG porous plates.