• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.90-95
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• 2011

This paper presents the study on the contact stress analysis of a pair of mating helical gears for turbo blower during rotation. Turbo blowers need high speed rotation of impeller in structure and high rate gear ratio. The use of helical gear indicated that noise was an important problem when the application involves high speeds and large power transmission. An example is presented to investigate the variation of contact stress on a pair of mating gears with contact positions. The variation of contact stress during rotation is compared with the contact stress at the lowest point of single tooth contact(LPSTC) and AGMA Equation for contact stress. In this study, the gear design considering the contact stress on a pair of mating gear is more severe than that of AGMA standard.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.1
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• pp.181-210
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• 1997

The stress distribution generated in the surrounding bone was calculated and compared for various geometry of the dental implants by means of the finite element methods. The models were designed to represent the screw type endosseous implants(varing the size, shape, direction of the screw thread and the angle of the body) with supporting bone and the cylinder type endosseous implants(varing the lower portion-Round type, tapered type) with supporting bone. Static mean bite forces were applied 100N vertically and 25N horizontally on the center of the implant and three dimensional finite analysis was undertaken using software ANSYS 5.1 Version. The result demonstrated that different implant shape leads to significant variations in stress distribution in the bone. In the case of variation of the screw size, direction and shape the implant model with normally directional and triangular screw implied lower stress than with upper directional or lower directional and quadrangular screw but among models a different screw size, within a variation of 0.2mm there was no meaningful difference in maximum stress. In the case of variation of angle of body the straight implied lower stress than the tapered. As a result of analysis of cylinder type, the implants with larger radius of curvature of the round form and larger diameter of the tapered form implied lower stress.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.68-78
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• 1993

Fatigue crack shape variation by a residual stress during crack growth and life predition are studied. An analytical method is presented to predict the influence of a residual stress due to heattreatment on crack shape variations. Computer simulation results using this me thod are graphically shown that crack growth rate to surface direction are decreased due to compressive residual stress exisiting in surface area. These results are commpared with experimental results. The fatigue life is also predicted by computer simulation of crack aspect ratio variation which is based on the surface crack length increment per unit cycle calculated from a-N diagram. Predited life is about 12 percent lower than experimental life.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.136-144
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• 1997

The characteristics of fatigue crack growth subject to out-of-plane bending fatigue are studied in terms of crack opening behavior by using pre-cracked smooth specimens. Crack opening stress is measured by an elastic compliance method which may precisely and continuously provide many date using strain gages during experiment. The results of the short crack and the long crack arranged by crack closure concept show that the effective stress gange ratio of short crack is grester than that of long crack, and ano- malous growth behavior of short crack may be elucidated by the variation of crack opening stress. When the variation of fatigue crack growth rate is arranged versus effective stress intensity factor range. Iinear relation is held also for the short crack. It shows that growth behavior of short crack can be quantitatively represent- ed by the fracture mechanics parameter using effective stress intensity factor range.

• Journal of the Korean GEO-environmental Society
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• v.8 no.1
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• pp.5-11
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• 2007

Internal stress variation in the face slab concrete induced by reservoir water pressure may affect on the stability of the dam so that the reclamation type of strain gauge is applied for measuring internal stress variation. In this study, internal as well as external stress variation of dam was measured by using strain gauge that was reclaimed to the ${\circ}{\circ}$ dam. In the result, it was confirmed that other measurements by relevant gauges need to be supplemented as the use of strain gauge only is insufficient to evaluate the stability analysis and global behavior of the dam.

• Kyungpook Mathematical Journal
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• v.55 no.3
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• pp.715-730
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• 2015

In this note, we extend the definition of harmonic and biharmonic maps via the variation of energy and bienergy between two Riemannian manifolds. In particular we present some new properties for the generalized stress energy tensor and the divergence of the generalized stress bienergy.

• Tunnel and Underground Space
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• v.14 no.5
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• pp.339-344
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• 2004

Variation of horizontal to vertical stress ratio of transversely isotropic rock caused by erosion was studied by numerical analysis. Influence of transversely isotropic was less than 5% for isotropic case. Difference between stresses obtained by numerical analysis and theoretical solution was small when initial stress ratio was small and the difference increased as erosion depth increased. Stress ratios diverged from initial ones as depth increased. An equation to determine stress ratio considering erosion according to the analyses was suggested.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.841-844
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• 1997

Sandwich structure is widely used in various fields of industry due to its excellent strength and stiffness compared with weight. We studied the buckling and bending behavior with respect to the variation of design parameters such as length, height, and thickness of honeycomb sandwich core. We found that as the density and the thickness of core become higher, the value of critical bucking load increased significantly. We found that the effect of bending stress due to critical buckling load resulted in high bending stress and the value of bending stress decreased in half according to the increase of length of core. The effect by bending stress is dominant above the portion of the intersection line between bending stress and the effect of buckling is dominant below the potion of it. We could get proper thickness ratio and density of core according to applied load conditions.

• Transactions of Materials Processing
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• v.19 no.7
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• pp.405-410
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• 2010

Double layered tube that has been used for transportation and oil piping system is occasionally exposed to elevated temperature. The change in stress state at elevated temperature is important for the safe design of double layered tube. In this study, the variation of stress state for hydroformed double layered tube of which inner tube is stainless steel and outer tube is mild steel has been analytically analyzed. To characterize the thermal stress at elevated temperature, analytical model to provide thermal stresses between outer tube and inner tube was developed by using theories of elasticity and Lame equation. The feasibility of analytical model is verified by finite element analysis using ANSYS $CLASSIC^{TM}$, commercially available code. The variation of thermal stress at various thickness combination of inner and outer tube has also been investigated by proposed analytical model.

• Advances in materials Research
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• v.5 no.2
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• pp.81-92
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• 2016

Stress concentration is an interesting and essential field of study, as it is the prime cause of failure of structural parts under static load. In the current paper, stress and strain concentration factors in unidirectional functionally graded (UDFGM) plate with central circular cutout are predicted by carrying out a finite element study on ANSYS APDL platform. The present study aims to bridge the lacuna in the understandings of stress analysis in perforated functionally graded plates. It is found that the material variation parameter is an important criterion while designing a perforated UDFGM plate. By selecting a proper material variation parameter and direction of material gradation, the stress and strain concentrations can be significantly reduced.