• Advances in aircraft and spacecraft science
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• v.10 no.3
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• pp.281-302
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• 2023

In this paper, bending analysis of exponentially varying functionally graded (FG) plate is presented using trigonometric shear deformation theory (TSDT) considering both transverse shear and normal deformation effects. The in-plane displacement field consists of sinusoidal functions in thickness direction to include transverse shear strains and transverse displacement include the effect of transverse normal strain using the cosine function in thickness coordinate. The governing equations and boundary conditions of the theory are derived using the virtual work principle. System of governing equations, for simply supported conditions, Navier's solution technique is used to obtain results. Plate material properties vary across thickness direction according to exponential distribution law. In the current theory, transverse shear stresses are distributed accurately through the plate thickness, hence obviates the need for a shear correction factor. TSDT results are compared with those from other theories to ensure the accuracy and effectiveness of the present theory. The current theory is in excellent agreement with the semi-analytical theory.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.7
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• pp.632-638
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• 2004

In order to evaluate the effect of blasting vibration in buildings and it's resident located around blasting construction field in urban area, blasting vibration characteristics were measured by the vibration level, vibration velocity. The 250g and 750g of charged powder were used at the apartment and at the ground, respectively. In the measurement of the ground, 2 (perpendicularity) axis was the highest value in vibration level, but vertical direction was the highest value at 25 m point and longitudinal direction was the highest value at 50 m point in vibration velocity. The amount of measurement was high value when measuring point is higher than blasting source, while that of measurement was low value when measuring point is lower than blasting source. In the measurement of the apartment, Z axis was the highest value in vibration level, but in vibration velocity transverse direction was the highest value at ground, was vertical direction at 1st floor, was longitudinal direction at 3rd floor and was vertical and longitudinal direction at 5th floor. The vibration level and the vibration velocity of 50 m point showed higher correlation value than 25 m point at the ground, but those of 25 m point showed higher correlation value than 50 m point at the apartment.

• Laser Solutions
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• v.5 no.3
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• pp.1-8
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• 2002

Finite element analysis and experiment were peformed to estimate the fatigue strength for the lap joint of laser weld. To consider quantitatively residual stress which effects on the fatigue strength of the lap joint of laser weld, after three dimensional modeling for the longitudinal and transverse direction, residual stress fields in the weldment were calculated using thermo-elastic-plastic finite element analysis, then the equivalent fatigue stress considering the residual stress was obtained. To ensure reliability of calculated fatigue strength, fatigue tests were performed. The calculated and experimental results showed a good agreement. The fatigue strength considering a residual stress was lower than that of without considering a residual stress in the lap joint of laser welding. The fatigue strength in the transverse direction was higher than that of longitudinal direction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.10 s.241
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• pp.1407-1415
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• 2005

Strength change of an over-aged A12024 material was studied after being subjected to stages of severe plastic deformation by ECAP (Equal Channel Angular Pressing). Various kinds of strength value were measured using the conventional tensile test, Rockwell and Vickers hardness and the SP (small punch) test Due to limitation of the specimen size, tension test in transverse direction could not be conducted. Hence, SP test was employed for assessing the strength in transverse direction. Based on TEM observation the measured strength characteristics were explained based on the relation between microstructure, dislocation and strength. As the number of ECAP pass increases, the strength of A12024 was also increased. However, considerable change of strength, which is generally predicted, was not observed in this study. For the strength in transverse direction even decrease of the strength was observed after 6 passes of ECAP. It was argued that this decrease was due to dynamic recovery of dislocation density during or after ECAP processes at $150^{\circ}C$. The strength assessment equation proposed by the authors in the previous paper was shown to be very accurate. This argument was supported by comparing the results of conventional tensile test with those of SP test. It was also pointed that the Rockwell har(3ness value seemed to be able to represent the strength in the transverse direction.

• Earthquakes and Structures
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• v.16 no.2
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• pp.185-196
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• 2019

One of the shortcomings of seismic bridge design codes is the lack of clarity in defining the role of different seismic isolation systems with linear or nonlinear behavior in terms of R-factor. For example, based on AASHTO guide specifications for seismic isolation design, R-factor for all substructure elements of isolated bridges should be half of those expressed in the AASHTO standard specifications for highway bridges (i.e., R=3 for single columns and R=5 for multiple column bent) but not less than 1.50. However, no distinction is made between two commonly used types of seismic isolation devices, i.e., elastomeric rubber bearing (ERB) with linear behavior, and lead rubber bearing (LRB) with nonlinear behavior. In this paper, five existing bridges located in Iran with two types of deck-pier connection including ERB and LRB isolators, and two bridge models with monolithic deck-pier connection are developed and their R-factor values are assessed based on the Uang's method. The average R-factors for the bridges with ERB isolators are calculated as 3.89 and 4.91 in the longitudinal and transverse directions, respectively, which are not in consonance with the AASHTO guide specifications for seismic isolation design (i.e., R=3/2=1.5 for the longitudinal direction and R=5/2=2.5 for the transverse direction). This is a clear indicator that the code-prescribed R-factors are conservative for typical bridges with ERB isolators. Also for the bridges with LRB isolators, the average computed R-factors equal 1.652 and 2.232 in the longitudinal and transverse directions, respectively, which are in a good agreement with the code-specified R-factor values. Moreover, in the bridges with monolithic deck-pier connection, the average R-factor in the longitudinal direction is obtained as 2.92 which is close to the specified R-factor in the bridge design codes (i.e., 3), and in the transverse direction is obtained as 2.41 which is about half of the corresponding R-factor value in the specifications (i.e., 5).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.8 s.338
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• pp.41-46
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• 2005

Microstrip open-end and linear resonator are analyzed by method of moment (MoM) taking the entire-domain current distribution, found in literature, along the transverse direction of microstrip line. A transverse correlation function which incorporates permittivity, thickness and width of the line is derived. Numerical examples are investigated and compared with the available other data and methods in order to give the validity of the proposed method. It is found that the proposed method can generate more accurate results than the conventional methods.

• Journal of the Optical Society of Korea
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• v.13 no.4
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• pp.484-488
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• 2009

We investigate the characteristics of the surface mode formed at the single interface between dual singly negative medium layers. It is shown that the interface can support a mode which has polarization degeneracy and a vanishing propagation constant. That is, this surface mode is a polarization-independent one that does not propagate at all through the interface. The corresponding electric and magnetic field distributions become static along the longitudinal (guiding) direction (but not along the transverse direction) resulting in the formation of transverse-electric/longitudinalmagnetic or transverse-magnetic/longitudinal-electric modes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1733-1740
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• 2004

In the transverse flux linear induction motor(TFLIM) with the general secondary composed of conductor and back-yoke, there exists a magnetized force into the normal direction or the air-gap direction of the thrust motion as well as the thrust force. Therefore, the various methodologies have been tried to use the normal force by the two independent control variables of the multi-phase input. But, as the force depends inevitably and strongly on the thrust force, it is essential to decouple both forces for two control index. In this paper, we suggest a novel approach capable of compensating the couple between both forces and the control index by using the DC-biased multi-phase input, and then realizing the independent control of TFLIM.

• Journal of Welding and Joining
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• v.7 no.1
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• pp.42-50
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• 1989

The application of fracture mechanics is being increased gradually to assess the safety of welded structures containing crack. Fatigue crack propagation behavior and elastic-plastic fracture toughness J$_{IC}$ of home made flux cored wire(1.22mm) CO$_{2}$ weldments was discussed. Especially fatigue crack propagation test was carried out by .DELTA.K control instead of load control and elastic-plastic fracture toughness J$_{IC}$ was obtained by ASTM-R curve method on C.T.specimen in transverse direction of weldments. The results obtained are as follows; (1) Weld metal presented an almost complete similarity to base metal on fatigue crack propagation rate in transverse direction. (2) Weld metal was more than base metal on J$_{IC}$ value in transverse direction. (3) F.C.W. CO$_{2}$ weldments had an excellent characteristic of fatigue crack propagation rate and J$_{IC}$ in less than 50kg/mm$^{2}$ steel grade, this would result from that weld metal had good static strength.trength.

• Advanced Composite Materials
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• v.16 no.2
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• pp.151-166
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• 2007

High-cycle fatigue characteristics of quasi-isotropic carbon fiber reinforced plastic (CFRP) laminates [-45/0/45/90]s up to $10^8$ cycles were investigated. To assess the fatigue behavior in the high-cycle region, fatigue tests were conducted at a frequency of 100 Hz, since it is difficult to investigate the fatigue characteristics in high-cycle at 5 Hz. Then, the damage behavior of the specimen was observed with a microscope, soft X-ray photography and a 3D ultrasonic inspection system. In this study, to evaluate quantitative characteristics of both transverse crack propagation and delamination growth in the high-cycle region, the energy release rate associated with damage growth in the width direction was calculated. Transverse crack propagation and delamination growth in the width direction were evaluated based on a modified Paris law approach. The results revealed that transverse crack propagation delayed under the test conditions of less than ${\sigma}_{max}/{\sigma}_b$ = 0.3 of the applied stress level.