OS0507 Method to Estimate the Steady-state Creep Deformation for the Solder Joint by Indentation Test

2014 ◽  
Vol 2014 (0) ◽  
pp. _OS0507-1_-_OS0507-2_
Author(s):  
Atsuko TAKITA ◽  
Katsuhiko SASAKI ◽  
Ken-ichi OHGUCHI
Keyword(s):  
Steady State ◽  
Solder Joint ◽  
Creep Deformation ◽  
Indentation Test ◽  
Steady State Creep

Evaluation of the Stress Distribution by the Stepped Load Indentation Test with Constant Depth

2016 ◽  
Vol 725 ◽  
pp. 293-298
Author(s):  
Atsuko Takita ◽  
Katsuhiko Sasaki ◽  
Ken-Ichi Ohguchi ◽  
H. Fujiki
Keyword(s):  
Steady State ◽  
Solder Joint ◽  
Creep Test ◽  
Creep Deformation ◽  
Indentation Test ◽  
Transient Creep ◽  
Steady State Creep ◽  
Indentation Creep ◽  
Stress Variation ◽  
Indentation Process

For accurate evaluation of the reliability of electronic package, FEM analyses considering the creep deformation of solder joint in-situ should be conducted. It is well known that the indentation creep test has an advantage to evaluate the creep deformation in microscopic region although there are the problems. Authors already modified the indentation creep test and proposed the method to estimate the steady state creep deformation by the modified test. For lead free solders generally used for the solder joint, the transient creep deformation should be measured by the indentation test in addition to the steady state creep deformation. The transient creep strain occurs in the indentation process. Therefore, it needs to separate the strain into the elastic-plastic strain and the creep strain. In this paper, the method to obtain the stress-strain relation using the indentation test is proposed. New indentation test used the stepped load was proposed to obtained the stress variation during the indenter was pushed and conducted by the numerical test. The suitable measurement point to obtain the relationship between the stress and the strain was identified. The stress variation estimated by proposed area well coincides with the equivalent stress variation of the nodal solution. Therefore, if the method to obtain the strain variation during the indentation process by the indentation in future is developped, it may be possible to estimate the stress-strain curve expressed the uniaxial deformation in the microscopic region.

Approximate analysis of transient creep deformation

1968 ◽  
Vol 3 (4) ◽  
pp. 288-296 ◽  
Author(s):  
D L Marriott
Keyword(s):  
Steady State ◽  
Creep Deformation ◽  
Creep Behaviour ◽  
Transient Creep ◽  
Steady State Creep ◽  
Approximate Analysis ◽  
Numerical Examples ◽  
Important Group

A method has been proposed which approximates transient creep behaviour by the superposition of elastic and steady-state creep deformation. The present paper discusses the errors incurred by this method. It is shown that they are small. Equations are derived which enable corrections to be calculated with moderate accuracy for an important group of creep theories. Some numerical examples are included for comparison.

scholarly journals ɤ-TiAl Alloy: Tensile Creep Deformation Behaviour and Creep Life at 832 °C

2021 ◽  
Author(s):  
Mainak Saha
Keyword(s):  
Steady State ◽  
Creep Deformation ◽  
Original Work ◽  
Single Phase ◽  
Tial Alloy ◽  
Deformation Behaviour ◽  
Steady State Creep ◽  
Tensile Creep ◽  
Creep Life ◽  
Processing Techniques

Creep deformation in single phase ɤ-TiAl alloy manufactured using different processing techniques has been an extensively studied topic since the late 1970s. The present work revisits the original work on understanding the tensile creep deformation behaviour of wrought single-phase ɤ-TiAl alloy by Hayes and Martin [1] and is aimed to develop an understanding of steady state creep. Besides, it is also aimed to investigate the creep life for stress levels of 69.4 and 103.4 MPa at 832 ⁰C using Monkman-Grant [2] approach.

A Theoretical Approach to Creep Deformation During Intermittent Load

1971 ◽  
Vol 93 (2) ◽  
pp. 205-210 ◽  
Author(s):  
R. Lagneborg
Keyword(s):  
Steady State ◽  
Applied Stress ◽  
Creep Deformation ◽  
Theoretical Approach ◽  
Steady State Creep ◽  
Numerical Computations ◽  
Stress Cycle ◽  
Creep Theory ◽  
Cyclic Stresses ◽  
Intermittent Loading

The influence of intermittent loading on creep deformation has been examined in terms of the recovery creep theory. It has been shown that according to this theory a material exposed to cyclic stresses of the same sign always creeps at a rate that is larger than the average of the steady state creep rates at the various stresses. Numerical computations have been performed in order to show how this accelerated strain depends on the applied stress and the time of the stress cycle.

scholarly journals Transversely Isotropic Creep Characteristics and Damage Mechanism of Layered Phyllite Under Uniaxial Compression Creep Test

2021 ◽  
Author(s):  
Jiabing Zhang ◽  
Xiaohu Zhang ◽  
Zhen Huang ◽  
Helin Fu
Keyword(s):  
Steady State ◽  
Uniaxial Compression ◽  
Creep Deformation ◽  
Transversely Isotropic ◽  
Damage Mechanism ◽  
Steady State Creep ◽  
Creep Stage ◽  
Compression Creep ◽  
Bedding Angle ◽  
Creep Characteristics

Abstract The layered surrounding rocks of deep tunnels undergo large creep deformation due to the presence of planes of weakness and the presence of prolonged high in-situ stress, thereby the deformation severely endangers the safety of tunnels. This study conducts uniaxial compression creep tests to experimentally investigate the transversely isotropic creep characteristics and the damage mechanism of layered phyllite samples having bedding angles of 0°, 22.5°, 45°, 67.5°, and 90°. The results indicate that the creep deformation of the specimens takes place in four stages: the instantaneous elastic deformation stage, the deceleration creep stage, the steady-state creep stage, and the accelerated creep stage. The cumulative creep deformation and the creep time during the steady-state creep stage of the specimens initially decrease and then increase as the bedding angle changes from 0° to 90°, thereby, corresponding to the initial increase and subsequent decrease in creep rate during the deceleration creep stage. Based on the existing viscoelastic-plastic damage creep model, the creep parameters E1, E2, η2, and η3 are observed to initially decrease and then increase with the increase in bedding angle, hence demonstrating that the creep characteristics and damage mechanism of the layered rock mass are controlled by the effect of the natural weakness planes and show significant transversely isotropic characteristics.

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