scholarly journals Mathematical model in a thin non-homogeneous rotating disc for isotropic material with rigid shaft by using Seth's transition theory

2015 ◽  
pp. 11-22
Author(s):  
Thakur Pankaj ◽  
Kaur Jatinder ◽  
Bir Satya
Author(s):  
J. W. Chew ◽  
S. Dadkhah ◽  
A. B. Turner

Sealing of the cavity formed between a rotating disc and a stator in the absence of a forced external flow is considered. In these circumstances the pumping action of the rotating disc may draw fluid into the cavity through the rim seal. Minimum cavity throughflow rates required to prevent such ingress are estimated experimentally and from a mathematical model. The results are compared with other workers’ measurements. Measurements for three different types of rim seal are reported for a range of seal clearances and for rotational Reynolds numbers up to 3 × 106. The mathematical model is found to correlate the experimental data reasonably well.


2016 ◽  
Vol 33 (3) ◽  
Author(s):  
Dr Pankaj Thakur ◽  
Jatinder Kaur ◽  
Satya Bir Singh

Purpose The purpose of this paper is to present study of thermal creep stresses and strain rates in a circular disc with shaft having variable density by using Seth’s transition theory. Design/methodology/approach Seth’s transition theory is applied to the problem of thermal creep transition stresses and strain rates in a thin rotating disc with shaft having variable density by finite deformation. Neither the yield criterion nor the associated flow rule is assumed here. The results obtained here are applicable to compressible materials. If the additional condition of incompressibility is imposed, then the expression for stresses corresponds to those arising from Tresca yield condition. Findings Thermal effect increased value of radial stress at the internal surface of the rotating disc made of incompressible material as compared to tangential stress and this value of radial stress further much increases with the increase in angular speed as compared to without thermal effect. Strain rates have maximum values at the internal surface for compressible material. Originality/value The model proposed in this paper is used in mechanical and electronic devices. They have extensive practical engineering application such as in steam and gas turbines, turbo generators, flywheel of internal combustion engines, turbojet engines, reciprocating engines, centrifugal compressors and brake disks.


2015 ◽  
Vol 93 ◽  
pp. 151-165 ◽  
Author(s):  
T. Skybová ◽  
M. Přibyl ◽  
P. Hasal

2011 ◽  
Vol 255-260 ◽  
pp. 14-19 ◽  
Author(s):  
Hong Zhang ◽  
Xiao Hui Ren

An Optimality Criteria method for topology optimization of continuum structures based on Solid Isotropic Material with Penalization (SIMP) was proposed. The minimum compliance of structures was selected as the objective function of the problem. A mathematical model for topology optimization design of statically loaded structures and the update scheme for the design variables were set. The examples showed that the algorithm has good convergence and application values.


2014 ◽  
Vol 10 (2) ◽  
pp. 211-227 ◽  
Author(s):  
Sanjeev Sharma ◽  
Ila Sahay ◽  
Ravindra Kumar

Purpose – The purpose of this paper is to provide the guidance on a design and integrity evaluation of a cylinder under pressure, for which stress analysis has been done for transversely isotropic thick-walled circular cylinder under internal and external pressure with thermal effects. Design/methodology/approach – Transition theory has been used to evaluate plastic stresses based on the concept of generalized principal Lebesgue strain measure which simplifies the constitutive equations and helps to achieve better agreement between the theoretical and experimental results. Findings – It can be concluded that circular cylinder with thermal effects under internal and external pressure made of isotropic material (steel) is on the safer side of the design as compared to the cylinder made of transversely isotropic material (i.e. magnesium and beryl) because percentage increase in effective pressure required for initial yielding to become fully plastic is high for isotropic material (steel) as compared to transversely isotropic material (i.e. magnesium and beryl). It can also be concluded that out of two transversely isotropic materials, beryl is better choice for design of cylinder as compared to magnesium material because percentage increase in effective pressure required for initial yielding to become fully plastic is high for beryl as compared to magnesium. Originality/value – A detailed investigation of thermal transversely isotropic thick-walled circular cylinder under internal and external pressure has been done which leads to the idea of “stress saving” that minimizes the possibility of fracture of cylinder.


2007 ◽  
Vol 96 (2) ◽  
pp. 169-179 ◽  
Author(s):  
M.J. O’Dogherty ◽  
R.J. Godwin ◽  
A.P. Dedousis ◽  
J.L. Brighton ◽  
N.D. Tillett

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
A. K. Aggarwal ◽  
Richa Sharma ◽  
Sanjeev Sharma

The objective of this paper is to provide guidance for the design of the thick-walled cylinder made up of transversely isotropic material so that collapse of cylinder due to influence of internal and external pressure can be avoided. The concept of transition theory based on Lebesgue strain measure has been used to simplify the constitutive equations. Results have been analyzed theoretically and discussed numerically. From this analysis, it has been concluded that, under the influence of internal and external pressure, circular cylinder made up of transversely isotropic material (beryl) is on the safer side of the design as compared to the cylinders made up of isotropic material (steel). This is because of the reason that percentage increase in effective pressure required for initial yielding to become fully plastic is high for beryl as compared to steel which leads to the idea of “stress saving” that reduces the possibility of collapse of thick-walled cylinder due to internal and external pressure.


Author(s):  
John W. Chew

Sealing of the cavity formed between a stationary disc and a rotating disc under axisymmetric conditions is considered. A mathematical model of the flow in the cavity based on momentum integral methods is described and this is coupled to a simple model of the seal for the case when no ingress occurs. Predictions of the minimum imposed flow required to prevent ingress are obtained and shown to be in reasonable agreement with the data of Bayley and Owen (1970), Owen and Phadke (1982), Phadke (1982), and Phadke and Owen (1982, 1983, 1988). With an empirical constant in the model chosen to match this data predictions for the minimum sealing flow are shown to be in good agreement with Graber et al’s (1987) measurements. The analysis of Phadke’s data also indicates the measurements for small seal clearances must be viewed with caution due to errors in setting the seal clearance. These errors are estimated to be twice the minimum clearance considered. Seal behaviour when ingress occurs is also considered and estimates of the amount of ingress are made from the available data.


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