• The Journal of Korean Academy of Prosthodontics
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• v.18 no.1
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• pp.15-35
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• 1980

The purpose of this study was to investigate stresses in the various components of fixed partial dentures restoring the posterior teeth of the lower jaw, and to measure quantitatively the effects of certain modifications in structural design on the stresses in the restorations using two-dimensional photoelasticity. Two-dimensional photoelastic methods were used in this study. Several models of fixed partial dentures were constructed. Shoulder less margins and anatomic occlusal reduction were incorporated in Model 1. Rounded shoulders and flat occlusal reduction were incorporated in Model 2, while Model 3 was a cantilever fixed partial denture. Other similar fixed partial dentures were constructed with V and U notches deliverately included in the region of the fixed joints for comparative reasons. The birefringent materials used in this study were PSM-1 and PSM-5 in standard sheets. PSM-1 was used for constructing the substructure, and PSM-5 was used in making the components of the fixed partial dentures. The two materials were used in the construction of composite photoelastic models. Improved artificial stone was used to represent dental cement in luting the composite photoelastic models. Static loading procedures were used at preplanned sites to represent occlusal loads in the mouth. 35 mm color and B/W film were used to record isochromatics in accordance with photoelastic procedures. Data reduction was performed using the grid method, which helped in, the mathematical integration procedure (Shear difference method) to separate the principal stresses. The results were as follows. 1. Fixed partial dentures do not function in bending as a symmetrical beam. Alternate areas of tension and compression were demonstrated when multiple contact loading was used. 2. The weakest part in posterior fixed partial dentures is the fixed joint. 3. (1) Models I and modified Model I were loaded on the pontic using a 50 pound vertical static load. The shear stress near the posterior fixed joint in Model 1 (U notches) was+129.4 p.s.i., and at the same fixed joint in modified Model 1 (V notches) was+239.4 p.s.i. The concentration of stress in fixed joint was reduced by 50% when U notches replaced the V notches. (2) Modified Model 2 was loaded using a multiple contact loader at a total load of 125 pounds. The difference between the principal stresses (${\sigma}_1-{\sigma}_2$), shear stress, at the V notches was+600 p.s.i., and at the U notches was+3l7 p.s.i. The shear stress was reduced by 50% when U notches replaced the V notches. V-grooves at the fixed joints should be avoided, and should be replaced by regular shaped U-grooves. 4. Cantilever fixed partial dentures had much higher stresses at the fixed joint than fixed partial dentures that were attached at both ends.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.35-42
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• 2003

This paper provides the first known flexural vibration data for thick (Mindlin) rectangular plates having V-notches. The V-notch has bending moment and shear force singularities at its sharp corner due to the transverse vibratory bending motion. Based upon Mindlin plate theory, in which transverse shear deformation and rotary inertia effects are considered, the Ritz procedure is employed with a hybrid set of admissible functions assumed for the rotational and transverse vibratory displacements. This set includes: (1) a mathematically complete set of admissible algebraic-trigonometric polynomials which guarantee convergence to exact frequencies as sufficient terms are retained; and (2) an admissible set of Mindlin corner functions which account for the bending moment and shear force singularities at the sharp corner of the V-notch. Extensive convergence studies demonstrate the necessity of adding the Mindlin corner functions to achieve accurate frequencies for rectangular plates having sharp V-notches.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.209-214
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• 1999

Dynamic pressure is one of the major sources on noise emission in hydraulic axial piston pump. This paper reports an experimental study of dynamic pressure characteristics in the cylinder port of hydraulic axial piston pump. We investigated dynamic pressure with not only the effect of delivery pressure, rotational speed and temperature but also V-notches at the ends of the kidney ports in the valve plate. We experimented three valve plates with three type V-notches at the ends of the kidney ports, because V-notches of the valve plate is known of noise reduction. Finally, we hope this paper help to design of the valve plate in hydraulic axial piston pump.

• Journal of Biosystems Engineering
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• v.1 no.1
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• pp.64-72
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• 1976

This experimental work was carried out to investigate the fatigue bending strength on various shapes and sizes of notches of the domestically manufactured steel plate. The notch types tested were a circular hole, U-and V-notches. The S-N diagram for different notch shapes were discussed in relation to plan bending strength and stress concentration factor of notches .The results of the experiments are summarized as follows : (1) The difference between stress concentration factor and notch factor was greater as the radium of notch root became smaller, and these values approached to an identical value as the radium of notch root increased. (2) It was shown that the plane bending fatigue limit of bar without notch for the hotrolled steel having the tensile strength of 33.1kg/$mm^2$was 17.0kg/$mm^2$. (3) U-and V-notch had a greater effect of stress concentration factor on the endurance limit, but O-hole showed the same effect only for $\o\pm2mm$. (4) For the same radius of notch root, U-notch showed a lower value of fatigue limit compared to V-notch and O-hole.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.719-720
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• 2008

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.4
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• pp.336-343
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• 2004

This paper reports the first known free vibration data for thin rectangular plates with V-notches. The classical Ritz method is employed with two sets of admissible functions assumed for the transverse vibratory displacements. These sets include (1) mathematically complete algebraic-trigonometric polynomials which guarantee convergence to exact frequencies as sufficient terms are retained, and (2) corner functions which account for the bending moment singularities at the sharp reentrant corner of the Y-notch. Extensive convergence studies summarized herein confirm that the corner functions substantially enhance the convergence and accuracy of nondirectional frequencies for rectangular plates having the V-notch. In this paper, accurate frequencies and normalized contours of vibratory transverse displacement are presented for various notched plates, so that the effect of corner stress singularities may be understood.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.533-534
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• 2007

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.433-442
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• 2009

In this paper, new three-dimensional vibration data for the solid cylinders of the N-sided polygonal cross-section with V-notches or sharp cracks are presented, and a Ritz procedure is employed, which incorporates a mathematically complete set of algebraic-trigonometric polynomials in conjunction with an admissible set of edge functions that explicitly model the tri-axial stress singularities that exist along a terminus edge of the V-notch. Convergence studies demonstrate the necessity of adding the edge functions to achieve the accurate frequencies and mode shapes of N-sided polygonal cylindrical solids with stress singularities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1A
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• pp.39-48
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• 2012

This study deals with numerical determination of stress intensity factors of adhesively patch-repaired plates with cracks at V-shaped or semicircular notches. The p-convergent anisoparametric model are considered and then three-dimensional virtual crack closure technique is presented using formulations of anisoparametric elements. In assumed displacement fields of an element, strain-displacement relations and three-dimensional constitutive equations are derived with three-dimensional hierarchical shape functions expanded from one-dimensional Lobatto functions. Transfinite mapping technique is used to represent a circular boundary. The present model provides accuracy and simplicity in terms of stress concentration factor, stress distribution, the number of degrees of freedom, and non-dimensional stress intensity factor as compared with previous works in literatures. Stress intensity factors obtained by the three-dimensional virtual crack closure technique are estimated with respect to the variation of width of finite plate, radius of notch root, angular inclination of V-shaped notch, and crack length.

• Structural Engineering and Mechanics
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• v.49 no.4
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• pp.499-508
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• 2014

We apply the Finite Fracture Mechanics criterion to address the problem of a V-notched structure subjected to mode II loading, i.e., we provide a way to determine the direction and the load at which a crack propagates from the notch tip and express the critical conditions in terms of the generalized stress intensity factor. Weight functions for V-notch emanated cracks available in the literature allow us to implement the fracture criterion proposed in an almost completely analytical manner: the determination of the critical load and the direction of crack growth is reduced to a stationary point problem. A comparison with experimental data presented in the Literature concludes the paper.