• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.159-162
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• 2001

A combined finite element and experimental study based on the characteristic length method is performed to investigate the strength and behavior of the pin joint in composite control rod. The failure is estimated by the Yamada-Sun and Tsai-Wu criteria on the characteristic curve. The gap elements are used to simulate the contact between the pin and the composite fitting with hole. The accuracy and applicability of the method are validated by the joint tests. All the specimens were failed in the bearing mode in the test and finite element analysis, and good agreement was found between the predicted and test results on the joint strength of composite control rod.

• Journal of the Korean Society for Nondestructive Testing
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• v.8 no.1
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• pp.22-29
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• 1988

The optical method of reflected and transmitted caustics has been utilized in mechanics investigations. This relatively new experimental technique has been successfully applied on various fracture analysis such as static and dynamic c rack propagation studies, some elasticity problems and contact stress, etc, In this study, the stress intensity factors in thin polycarbonate specimens, a kind of optically anisotropic material, under Mode I loading condition are estimated by the method of caustics. The values of stress intensity factors obtained from theoretical caustics shape are compared by the experiment. It is confirmed that the two stress intensity factors agree well with Srawley's solution.

• Tribology and Lubricants
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• v.23 no.3
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• pp.89-94
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• 2007

The stress and displacement behavior analysis of an aluminum tube for an organic photo conductor drum has been presented using a finite element analysis technique by non-linear FEM program. The maximum displacement in the radial direction of OPC drum may directly affect to the quality of printed matter. Thus, the deformed profile of the aluminum tubes should be limited depending on the toner powder size and the contact rolling forces between an OPC drum and a paper. This paper recommends the critical loading of 400 Pa for the provided toner size, $8{\mu}m$ for excellent printed matters and long life of the toner cartridge.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.27-34
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• 2001

This paper discussed the shape effect of ceramic support carrier in order to facilitate biomass immobilization. The shape of ceramic support carrier was modified hollow pipe type into hollow gear type. After seeding, microorganisms were attached in crevices where protection from shear forces or surfaces where easy to contact with support carrier surface. In case of hollow gear type carrier, initial attachment rate was faster than that of hollow pipe type and obtained thick biofilm. Synthetic wastewater(COD:75~880 mg/L, organic loading rate:0.36~4.22 kgCOD/㎥.d) was treated aerobic fixed bed biofilm reactor where 100% of the volume was filled with the ceramic carrier. COD removal efficiency of reactor filled with gear type support carrier was a little high withing 70 days, and then showed similar removal efficiency. It was found that highly loaded operation with up to 4.22 kgCOD/㎥.d was possible in both reactor. Total biomass amounts of pipe type was higher than gear type, however, attached biomass of gear type was higher than that of pipe type.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.660-665
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• 2007

This Study is a structure analysis about twin lift telescopic Spreader that usually loading and unloading a container in harbor. Applied load is assumed by lifting 65tons that is the maximum weight of real container. The finite element analysis for 3D model is performed by ABAQUS/Standard. We made an estimate of safety by evaluating the results of the finite element analysis.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.1
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• pp.30-36
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• 2003

Brittle materials such as glasses and ceramics, which are very weak under impact loading, show fragile failure mode due to their low fracture toughness and crack sensitivity. When brittle materials are subjected to impact by small spheres, high contact pressure occurs at the impacted surface causing local damage on the specimen. This damage is a dangerous factor in causing the final fracture of structures. In this research, the crack propagation process of soda-lime glass by the impact of small spheres is explained and the effects of several constraint conditions for impact damage were studied by using soda-lime glass; that is, the effects for the materials and sizes of impact ball, thickness of specimen and residual strength were evaluated. Especially, this research has focused on the damage behavior of ring cracks, cone cracks and several other kinds of cracks.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.4
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• pp.33-37
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• 2007

Creep failure of 316LN stainless steel (SS) occurs due to the nucleation and growth of cracks. An investigation was performed to correlate the creep damage with ultrasonic wave speeds and angular frequencies using creep-tested 316LN SS specimens. Ultrasonic wave measurements were made in the direction of and perpendicular to the loading using contact probes with central frequencies of 10, 15, and 20 MHz. We found that the angular frequency and wave speed decreased with increasing creep time to rupture by analyzing the ultrasonic signals from the 15 and 20 MHz probes. Therefore, the creep damage was sensitive to the angular frequency and wave speed of ultrasonic waves.

• Structural Engineering and Mechanics
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• v.56 no.1
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• pp.85-106
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• 2015

Postbuckling of thick plates made of functionally graded material (FGM) subjected to in-plane compressive, thermal and thermomechanical loads is investigated in this work. It is assumed that the plate is in contact with a Pasternak-type elastic foundation during deformation. Thermomechanical non-homogeneous properties are considered to be temperature independent, and graded smoothly by the distribution of power law across the thickness in the thickness in terms of the volume fractions of constituents. By employing the higher order shear deformation plate theory together the non-linear von-Karman strain-displacement relations, the equilibrium and compatibility equations of imperfect FGM plates are derived. The Galerkin technique is used to determine the buckling loads and postbuckling equilibrium paths for simply supported plates. Numerical examples are presented to show the influences of power law index, foundation stiffness and imperfection on the buckling and postbuckling loading capacity of the plates.

• Computers and Concrete
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• v.18 no.1
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• pp.99-112
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• 2016

Since the preservation of monuments is very important to human societies, different methods are required to preserve historic structures. In this paper, 3D model of arch stone bridge at Pont Saint Martin, Aosta, Italy, was simulated by 1660 integrated separate stones using ABAQUS$^{(R)}$ software to investigate the seismic susceptibility of the bridge. The main objective of this research was to study a method of preservation of the historical stone bridge against possible earthquakes using FRP techniques. The nonlinear behavior model of materials used theory of plasticity based on Drucker-Prager yield criterion. Then, contact behavior between the block and mortar was modeled. Also, Seismosignal software was used to collect data related to 1976 Friuli Earthquake Italy, which constitutes a real seismic loading. The results show that, retrofitting of the arch stone bridge using FRP techniques decreased displacement of stones of spandrel walls, which prevents the collapse of stones.

• Transactions of Materials Processing
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• v.6 no.5
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• pp.408-415
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• 1997

The backward tracing scheme of the finite element analysis, which is counted to be unique and useful for process design in metal forming, has been developed and applied successfully in industry to several metal forming processes. Here the backward tracing scheme is implemented for process design of three-dimensional plastic deformation in metal forming, and it is applied to a precision coining process. The contact problem between the die and workpiece has been treated carefully during backward tracing simulation in three-dimensional deformation. The results confirm that the application of the developed program implemented with backward tracing scheme of the rigid plastic finite element leads to a reasonable initial piercing hole configuration. It is concluded that three-dimensional extension of the scheme appears to be successful for industrial applications.