• Structural Engineering and Mechanics
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• v.90 no.5
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• pp.517-530
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• 2024

This paper presents a new four-unknown equivalent single layer (ESL) refined plate theory for the buckling analysis of functionally graded (FG) rectangular plates with all simply supported edges and subjected to in-plane mechanical loading conditions. The present model accounts for a parabolic variation of transverse shear stress over the thickness, and accommodates correctly the zero shear stress conditions on the top and bottom surfaces of the plate. The material properties are supposed to vary smoothly in the thickness direction through the rules of mixture named power-law gradation. The governing equilibrium equations are formulated based on the total potential energy principle and solved for simply supported boundary conditions by implementing the Navier's method. A numerical result on elastic buckling using the current theory was computed and compared with those published in the literature to examine the accuracy of the proposed analytical solution. The effects of changing power-law exponent, aspect ratio, thickness ratio and modulus ratio on the critical buckling load of FG plates under different in-plane loading conditions are investigated in detail. Moreover, it was found that the geometric parameters and power-law exponent play significant influences on the buckling behavior of the FG plates.

• Structural Engineering and Mechanics
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• v.37 no.2
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• pp.253-256
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• 2011

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.4
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• pp.905-915
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• 1998

Static tensile tests using adhesive-bonded single-lap joints of aluminum alloy were conducted to investigate the effect of geometric factor, overlap length, adherend thickness, adhesive thickness and material composition of adherend/adhesive on the strength of adhesive joint. The average applied shear stress at joint fracture decreased with increasing lap length. However increasing the adherend thickness resulted in a higher joint strength. Higher yield strength of adherend and lower elastic modulus of adhesive is advantageous to the adhesive joint. Newly proposed modified joint factor could be well evaluated the influence of lap length, adherend thickness and adhesive thickness on the bond strength for adhesive joints.

• Journal of the Korean Ceramic Society
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• v.30 no.7
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• pp.549-556
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• 1993

Interfacial shear strength plays an important role in determining the mechanical properties of a fiber-reinforced ceramic composites. In this study, the effect ofinterlayer thickness on mechanical properties of Nicalon-fiber-reinforced SiC composites fabricated via polymer solution infiltration/chemical vapor infiltration (PSI/CVI) was studied. It was found that the flexural strength and fracture toughness of the composites were increased with the interlayer thickness and showed maximum value at the interlayer thickness of 0.66${\mu}{\textrm}{m}$. Typical flexural strength and fracture toughness of Nicalon-fiber-reinforced SiC composites with interlayer thickness of 0.66${\mu}{\textrm}{m}$ were 391.7$\pm$34.6MPa and 15.1$\pm$1.8MPa.m1/2, respectively.

• Structural Engineering and Mechanics
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• v.7 no.3
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• pp.319-330
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• 1999

The design of composite space trusses is a demanding task that involves taking several decisions on the truss depth, number of panels, member configuration, number of chord layers and concrete slab thickness and grade. The focus in this paper is on the design of top concrete slabs of composite space trusses, and in particular their thickness. Several effects must be considered in the process of designing the slab before an optimum thickness can be chosen. These effects include the inplane forces arising from shear interaction with the steel sub-truss and the flexural. and sheer effects of direct lateral slab loading. They also include a constructional consideration that the thickness must allow for sufficient cover and adequate space for placing the reinforcement. The work presented in this paper shows that the structural requirements on the concrete slab thickness are in many cases insignificant compared with the constructional requirements.

• Structural Engineering and Mechanics
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• v.73 no.3
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• pp.259-269
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• 2020

In this paper, bending-stretching analysis of thick functionally graded piezoelectric rectangular plates is studied using the higher-order shear and normal deformable plate theory. On the basis of this theory, Legendre polynomials are used for approximating the components of displacement field. Also, the effects of both normal and shear deformations are encountered in the theory. The governing equations are derived using the principle of virtual work and variational approach. It is assumed that plate is made of piezoelectric materials with functionally graded distribution of material properties. Hence, exponential function is used to modify mechanical and electrical properties through the thickness of the plate. Finally, the effect of material properties, electrical boundary conditions and dimensions are investigated on the static response of plate. Also, it is shown that results of the presented model are close to the three dimensional elasticity solutions.

• Geomechanics and Engineering
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• v.11 no.2
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• pp.289-307
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• 2016

A simple hyperbolic shear deformation theory taking into account transverse shear deformation effects is proposed for the free flexural vibration analysis of thick functionally graded plates resting on elastic foundations. By considering further supposition, the present formulation introduces only four unknowns and its governing equations are therefore reduced. Hamilton's principle is employed to obtain equations of motion and Navier-type analytical solutions for simply-supported plates are compared with the available solutions in literature to check the accuracy of the proposed theory. Numerical results are computed to examine the effects of the power-law index and side-to-thickness ratio on the natural frequencies.

• Journal of Mechanical Science and Technology
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• v.14 no.9
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• pp.920-927
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• 2000

A multi-layered orthotropic material with a center crack is subjected to an anti-plane shear loading. The problem is formulated as a mixed boundary value problem by using the Fourier integral transform method. This gives a Fredholm integral equation of the second kind. The integral equation is solved numerically and anti-plane shear stress intensity factors are analyzed in terms of the material orthotropy for each layer, number of layers, crack length to layer thickness and the order of the loading polynomial. Also, the case of monolithic and hybrid composites are investigated in terms of the local fiber volume fraction and the global fiber volume fraction.

• Journal of the Korean Society for Precision Engineering
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• v.1 no.2
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• pp.24-32
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• 1984

The object of the study is to discuss the effect of magic ink as a surface active substance on the mechanism of chip formation in oblique cutting. The Rehbinder effect has been known as a phenomenon that the mechanical strength reduces when the metal is coated with some surface active substances. In order to interpret these surface effects defined by Rehbinder, the influence on the shear strength of shear plane by coating surface active substances, cutting force by the depth of cut, surface roughness and hardness ratio were observed. The results are as follows: 1. By coating the magic ink on free surface of the forming chip, the effective shear angle increases, and the cuttinbg force and the deformed chip thickness decreases. 2. With the large inclination angle the effective shear angle increases, and the specific cutting force and the friction angle decrease. 3. Cutting of the coated surface improves the surface roughness and the hardness ratio drops, which means another Rehbinder effect.

• Journal of the Korean Society of Safety
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• v.17 no.1
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• pp.39-44
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• 2002

This paper shows error in the polarization direction on ultrasonic transducers how sensitive the shear ultrasonic waves are to a little misoriented plies according to the angle variation of shear ultrasonic waves $0{\circ},\;45{\circ}$ and $90{\circ}$. Also, it is shown that shear waves, particularly the transmission mode with the transmitter and receiver perpendicular to cach other, have high sensitivity for detecting anomalies in fiber orientation and ply layup sequence that may occur in the manufacturing of composite laminates. Experimental results are agreed with a modeling solutions which was based on decomposition of shear wave polarization vector as it propagates through the composite laminates. This wave appeared considerably to be sensitive to CFRP composites to thickness direction along in-plane fibers.