A DEGREE OF RESTRAINT:

2015 ◽  
pp. 68-87
Keyword(s):  
Degree Of Restraint

Optimization of Wet Cylinder Liner Designs for High Thermal Loadings

1972 ◽  
Vol 186 (1) ◽  
pp. 29-44
Author(s):  
R. Bertodo ◽  
D. Razdan
Keyword(s):  
Stress Level ◽  
Thermal Stresses ◽  
Cylinder Liner ◽  
Order Effect ◽  
Sound Design ◽  
Wear Properties ◽  
Thin Sections ◽  
Factors Affecting ◽  
Wear Process ◽  
Degree Of Restraint

The paper outlines the optimization of wet cylinder liner designs for high thermal loads, with special reference to medium speed diesel engine applications in the bore range 180–500 mm (∼ 7–20 in). It is shown that a flake graphite nickel–copper–molybdenum alloyed cast iron with a well developed vanadium matrix combines the best properties for liner manufacture. For quality control reasons, centrifugal castings are often preferred, although the resultant graphite form is unfavourable for thermal stress resistance. Consequently, recourse to plain steels is sometimes required, leading naturally to the adoption of chromed finishes for wear and corrosion resistance. For a given thermal rating, the thermal stresses can be reduced by a judicious choice of air–fuel ratio, but a limiting value exists beyond which the thermal stresses remain unaffected. Reductions in stress level are also possible by optimizing the wall thickness and coolant flow. This leads inevitably to thin sections susceptible to distortion under firing and impact loads, thus impairing both the strength of the component and its wear properties. A planned degree of restraint can be adopted to control both distortion and stress level; such measures are not always conducive to economic design and serviceability, and may actually degrade the reliability when applied to steel liners. The surrounding structure can have a first order effect on the stress levels in the liner; these manifest themselves as applied loads to the liner supports or flange. The design details are thus important, and the influence of parameters such as bolting load, location of sealing spigot and block deflection are discussed in relation to the evolution of successful designs. Any structurally sound design must be capable of operating for periods of 20 000 h or more without excessive wear. It is shown that the wear process is essentially exponential; the factors affecting its absolute value are discussed, and attempts made to quantify their contribution.

EFFECT OF THE DEGREE OF RESTRAINT AGAINST THERMAL EXPANSION AND CONTRACTION ON WELDING RESIDUAL STRESS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4075-4080
Author(s):  
SANG-HYONG LEE ◽  
KYONG-HO CHANG ◽  
GAB-CHUL JANG
Keyword(s):  
Residual Stress ◽  
Evaluation Method ◽  
Safety Evaluation ◽  
Residual Stress Distribution ◽  
Welding Residual Stress ◽  
Steel Bridge ◽  
Repair Work ◽  
Vehicle Load ◽  
Degree Of Restraint ◽  
A Chain

Steel bridges increased considerably since 1960's in Japan. That is due to the lightness and long trend in bridge construction. Bridges, which are damaged by an increase in vehicle load, corrosion, earthquake, and so on, need repairing or strengthening. Repair procedures of steel bridge generally include cutting, bolting and welding procedures. These procedures, cutting, bolting and welding, occasionally bring about a stress concentration within the limit range. So, a chain of confirmation against the safety of structure is necessary. A safety evaluation method, which has regard to heat effect, is necessary to repair damaged structure with welding. Generalized welding residual stress is useful employ, to estimate the safety of structure during the repair work with welding. This research investigates the features of thermal stress generated by welding. The pattern of welding residual stress distribution was classified according to the ratio between length and width of plate. With those results, the features of residual stress generated by welding were generalized.

State and Local Government Fiscal Constraints: Public Sector and Private Sector Effects

1984 ◽  
Vol 12 (4) ◽  
pp. 425-456 ◽  
Author(s):  
William F. Fox ◽  
Kenneth E. Quindry
Keyword(s):  
Public Sector ◽  
Private Sector ◽  
Economic Effect ◽  
Economic Effects ◽  
Fiscal Constraints ◽  
Tax Relief ◽  
Revenue Structure ◽  
State And Local Government ◽  
State And Local ◽  
Degree Of Restraint

The Tennessee Econometric Model is employed to simulate the effects of alternative fiscal limits on a state economy. Limits modelled on those currently in effect in California, Colorado, New Jersey, and Tennessee are applied using both an elastic and an inelastic revenue structure. Economic and fiscal effects depend on the elasticity of the revenue structure, the coverage of the limits, the degree of restraint imposed by the limit, whether business or individual taxes are reduced, and the timing of tax reductions. The limits have a greater constraining effect on elastic structures. A frequent effect of the limits is a reduction in the size of the public sector and a small increase in the private sector with the overall level of economic activity generally declining. Fiscal limits are found to have more stimulative economic effects if the tax relief is business-oriented, so that the net economic effect may be positive.

Design and Analysis of a Test Coupon for Fusion Welding

1993 ◽  
Vol 115 (1) ◽  
pp. 38-46 ◽  
Author(s):  
B. K. Jones ◽  
A. F. Emery ◽  
S. J. Marburger
Keyword(s):  
Weld Bead ◽  
Fusion Welding ◽  
Welding Parameters ◽  
Simple Test ◽  
Final State ◽  
Test Coupon ◽  
Degree Of Restraint ◽  
High Degree ◽  
Fusion Welds

The objective of a weld coupon is to provide a simple test to determine the effects of different welding parameters and constraints on the final state of fusion welds. With such a test it will be possible to judge the performance of a particular weld under known states of temperature and external restraint. This paper describes the experiments and analyses performed on a thin coupon with a circular weld bead which was designed to simulate a typical manufacturing geometry. The temperatures and deformations measured in the experiments corresponded closely to those of the analyses. It was found that such a geometry provides a high degree of restraint regardless of the radius of the circular weld bead. Experimental and analytical stresses indicate that extensive yielding occurs throughout the coupon.

Prediction of welding deformations of stiffened panels

2002 ◽  
Vol 216 (2) ◽  
pp. 133-143 ◽  
Author(s):  
C D Jang ◽  
C H Lee ◽  
D E Ko
Keyword(s):  
Strain Theory ◽  
Ship Hull ◽  
Design Stage ◽  
Stiffened Panel ◽  
Welding Deformation ◽  
The Finite Element Method ◽  
Stiffened Panels ◽  
Precise Method ◽  
Degree Of Restraint ◽  
Inherent Strain

Welding deformation reduces the accuracy of ship hull blocks and decreases productivity due to the need for correction work. Preparing an error-minimizing guide at the design stage will lead to higher quality as well as higher productivity. Therefore, developing a precise method to predict the weld deformation is an essential part of it. This paper proposes an efficient method for predicting the weld deformation of complicated structures based on the inherent strain theory combined with the finite element method. The inherent strain is defined as the residual plastic strain after the welding heat cycle and is determined using the highest temperature and degree of restraint. In order to calculate precisely the inherent strain in real structures, it should be noted that the degree of restraint changes according to the different fabrication stages. The simulation of a stiffened panel confirmed the applicability of this method to simple ship hull blocks.

Experimental Evaluation of Residual Stresses in the Concrete

2016 ◽  
Vol 835 ◽  
pp. 433-438
Author(s):  
Lukáš Zvolánek ◽  
Miroslav Kratochvíl ◽  
Jaroslav Kadlec ◽  
Ivailo Terzijski
Keyword(s):  
Elastic Modulus ◽  
Residual Stresses ◽  
Experimental Evaluation ◽  
Concrete Composition ◽  
Volume Changes ◽  
Free Shrinkage ◽  
Concrete Mixtures ◽  
Surrounding Environment ◽  
Eurocode 2 ◽  
Degree Of Restraint

Generally, volume changes commences almost immediately after the cement and water come in contact during concrete mixing. Humidity of surrounding environment affects the magnitude of shrinkage. Hence, we took it into account by means of Eurocode 2. This paper proposes the evaluation of residual stresses in concrete. To describe the development of residual stresses, magnitude of free shrinkage, degree of its restrain and corresponding value of elastic modulus has to be known. All required quantities was measured apart from degree of restraint. It was tested three types of concrete mixtures. Obtained results show that the free shrinkage value can be significantly reduced by technological way such as the change of concrete composition.

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