Biaxial Creep Strains at Notch Roots—Measurement and Modeling

1997 ◽  
Vol 119 (1) ◽  
pp. 46-50 ◽  
Author(s):  
H. Zeng ◽  
W. N. Sharpe
Keyword(s):  
Finite Element ◽  
Measurement Technique ◽  
Zirconium Alloy ◽  
Notch Root ◽  
Finite Element Code ◽  
Smooth Specimen ◽  
Interferometric Technique ◽  
Biaxial Creep ◽  
Creep Strains

Biaxial strains were measured at the roots of single notches in zirconium alloy specimens under loading and creep conditions (up to 1200 hours) at 250°C. A laser-based interferometric technique was used; details of the measurement procedures are given in another paper. Here, the Bodner model is incorporated into the ABAQUS finite element code and used to predict the biaxial strains at the notch root during loading and for a creep duration of 100 hours. The strains during loading agree quite well with the measured ones while the predicted creep strains are smaller. This discrepancy is attributed to the lack of precision in determining the constants for the Bodner model from smooth-specimen tests. Both the measurement technique and the Bodner model are well-suited for studies of notch response.

Viscoplastic Behavior of a Notch Root at 650°C: ISDG Measurement and Finite Element Modeling

1996 ◽  
Vol 118 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Keyu Li ◽  
William N. Sharpe
Keyword(s):  
Finite Element ◽  
Notch Root ◽  
Tensile Creep ◽  
Strain Gages ◽  
Controlled System ◽  
Interferometric Technique ◽  
Pure Silicon ◽  
Nickel Based Superalloy ◽  
Silicon Coating ◽  
Computer Controlled

Viscoplastic behavior of the nickel-based superalloy, Inconel 718, at a notch root has been investigated by conducting isothermal tensile, creep and cyclic elastoplastic tests at 650°C which is the working temperature of the material in aircraft engines. A laser-based interferometric technique was extended to measure biaxial strains over a gage length of 150 μm at the notch root; the computer controlled system permits real-time measurements. A thin-film pure silicon coating and an argon atmosphere were used to prevent oxidation of the reflective indentations that serve as the strain gages. The measured strains were used to evaluate the Bodner-Partom constitutive model which was incorporated into the ABAQUS finite element code. Material constants in the model were determined from uniaxial tests on smooth specimens. The predicted strains agree reasonably well with the measured ones for all three kinds of loadings.

Elasto-plastic and creep behaviour of axially loaded, shouldered tubes

1980 ◽  
Vol 15 (1) ◽  
pp. 21-29 ◽  
Author(s):  
R J Dawson ◽  
H Fessler ◽  
T H Hyde ◽  
J J Webster
Keyword(s):  
Finite Element ◽  
Creep Behaviour ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Equivalent Strain ◽  
Uniaxial Tensile ◽  
Plastic Strain Increment ◽  
Axially Loaded ◽  
Initial Strains ◽  
Creep Strains

This paper compares the finite element predictions of elasto-plastic and creep behaviour with experimental data for axially loaded, shouldered tube models. Four shouldered tube models were made of a lead alloy and tested at 61°C, using strain gauges to measure the elasto-plastic and creep strains in the plain tube and fillet regions of the models. Instantaneous stress-strain and creep data were obtained from strain-gauged, uniaxial tensile specimens. The finite element solutions are based on the incremental Prandtl-Reuss equations. The elasto-plastic iterative solutions use a ‘negative gradient’ from the calculated point to the equivalent stress-equivalent strain curve to get the next estimate of the plastic strain increment. A time incremental method is used to obtain the creep solutions. Tests with the mean tube stress below, at and above the yield stress showed very good agreement between prediction and measurement of initial strains in the fillets. Differences between predictions and measurements of creep strains are attributable to cast-to-cast variations.

Design of object oriented finite element code

2001 ◽  
Vol 32 (10-11) ◽  
pp. 759-767 ◽  
Author(s):  
B Patzák ◽  
Z Bittnar
Keyword(s):  
Finite Element ◽  
Object Oriented ◽  
Finite Element Code

Python-based finite element code used as a universal and modular tool for electronic structure calculation

2013 ◽  
Author(s):  
Robert Cimrman ◽  
Miroslav Tůma ◽  
Matyáš Novák ◽  
Ondřej Čertík ◽  
Jiří Plešek ◽  
...  
Keyword(s):  
Finite Element ◽  
Electronic Structure ◽  
Structure Calculation ◽  
Electronic Structure Calculation ◽  
Finite Element Code

A Finite Element Analysis for Magnetostrictive Thin Film Structures and Its Experimental Verification

2006 ◽  
Vol 306-308 ◽  
pp. 1151-1156 ◽  
Author(s):  
Chong Du Cho ◽  
Heung Shik Lee ◽  
Chang Boo Kim ◽  
Hyeon Gyu Beom
Keyword(s):  
Thin Film ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Geometric Feature ◽  
Hysteresis Phenomenon ◽  
Finite Element Code ◽  
Element Analysis ◽  
Element Mesh ◽  
Magnetostrictive Actuators ◽  
Large Length

In this paper, a finite element code especially for micro-magnetostrictive actuators was developed. Two significant characteristics of the presented finite element code are: (1) the magnetostrictive hysteresis phenomenon is effectively taken into account; (2) intrinsic geometric feature of typical thin film structures of large length to thickness ratio, which makes it very difficult to construct finite element mesh in the region of the thin film, is considered reasonably in modeling micro-magneostrictive actuators. For verification purpose, magnetostrictive thin films were fabricated and tested in the form of a cantilevered actuator. The Tb-Fe film and Sm-Fe film are sputtered on the Si and Polyimide substrates individually. The magnetic and magnetostrictive properties of the sputtered magnetostrictive films are measured. The measured magnetostrictive coefficients are compared with the numerically calculated ones.

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