CRACK DETECTION USING INDUCTION THERMOGRAPHY FOR THERMOMECHANICAL FATIGUE TESTS

2011 ◽  
Author(s):  
M. Genest ◽  
D. C. Dudzinski ◽  
S. Bulmer ◽  
R. K. Kersey ◽  
Donald O. Thompson ◽  
...  
Keyword(s):  
Crack Detection ◽  
Thermomechanical Fatigue ◽  
Fatigue Tests

Thermomechanical Fatigue Tests Development and Life Prediction of a Nickel Base Superalloy

2016 ◽  
Vol 40 (2) ◽  
pp. 777-787 ◽  
Author(s):  
A. García de la Yedra ◽  
J. L. Pedrejón ◽  
A. Martín-Meizoso ◽  
R. Rodríguez
Keyword(s):  
Life Prediction ◽  
Thermomechanical Fatigue ◽  
Fatigue Tests ◽  
Nickel Base Superalloy ◽  
Nickel Base ◽  
Base Superalloy

Thermomechanical Fatigue Life Prediction of 63Sn/37Pb Solder

1992 ◽  
Vol 114 (2) ◽  
pp. 145-151 ◽  
Author(s):  
Q. Guo ◽  
E. C. Cutiongco ◽  
L. M. Keer ◽  
M. E. Fine
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Life Prediction ◽  
Strain Range ◽  
Thermomechanical Fatigue ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Fatigue Life Prediction ◽  
Total Strain ◽  
Isothermal Fatigue

Isothermal and thermomechanical fatigue of 63Sn/37Pb solder is studied under total strain-controlled tests. A standard definition of failure is proposed to allow inter-laboratory comparison. Based on the suggested failure criterion, load drop per cycle, the Young’s modulus and the ratio of the maximum tensile to maximum compressive stresses remain constant, and the fatigue response of the solder is stable before failure, although cyclic softening was observed from the beginning. Experimental results of isothermal fatigue tests for a total strain range from 0.3 to 3 percent show that the log-log plot of the number of cycles to failure versus the plastic strain range has a kink at the point where the elastic strain is approximately equal to the plastic strain. In this paper, it is shown how the isothermal fatigue life of near-eutectic solder at lower strain ranges can be predicted by using the experimental data of fatigue tests at high strain ranges and early stage information of a fatigue test at the strain range in question. A thermomechanical fatigue life prediction is also given based on a dislocation pile-up model. Comparison with experimental results shows a good agreement.

Thermomechanical Fatigue Behavior of a Quasi-lsotropic SCS-6/Ti-15-3 Metal Matrix Composite

1995 ◽  
Vol 117 (1) ◽  
pp. 109-117 ◽  
Author(s):  
K. A. Hart ◽  
S. Mall
Keyword(s):  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Stress Level ◽  
Metal Matrix ◽  
Maximum Stress ◽  
Fatigue Behavior ◽  
Thermomechanical Fatigue ◽  
Fatigue Tests ◽  
Microscopic Evaluation ◽  
Observed Damage

The response of a quasi-isotropic laminate of metal matrix composite, SCS-6/Ti-15-3 in a thermomechanical fatigue (TMF) environment was investigated. To achieve this, three sets of fatigue tests were conducted: 1) in-phase TMF (IP-TMF), 2) out-of-phase TMF (OP-TMF), and 3) isothermal fatigue (IF). The fatigue response was dependent on the test condition and the maximum stress level during cycling. The IF, IP-TMF, and OP-TMF conditions yielded shortest fatigue life at higher, intermediate and lower stress levels, respectively. Examination of the failure mode through the variation of strain or modulus during cycling, and post-mortem microscopic evaluation revealed that it was dependent on the fatigue condition and applied stress level. Higher stresses, mostly with IP-TMF and IF conditions, produced a primarily fiber dominated failure. Lower stresses, mostly with the OP-TMF condition, produced a matrix dominated failure. Also, an empirical model based on the observed damage mechanisms was developed to represent the fatigue lives for the three conditions examined here.

scholarly journals Modeling Stiffness Degradation of Fiber-Reinforced Polymers Based on Crack Densities Observed in Off-Axis Plies

2021 ◽  
Vol 6 (1) ◽  
pp. 10
Author(s):  
Matthias Drvoderic ◽  
Martin Pletz ◽  
Clara Schuecker
Keyword(s):  
Shear Stress ◽  
Crack Detection ◽  
Crack Density ◽  
Damage Parameter ◽  
Fatigue Tests ◽  
Fiber Reinforced Polymers ◽  
Stiffness Degradation ◽  
Plane Shear ◽  
Matrix Cracks ◽  
Using Data

A model that predicts the stiffness degradation in multidirectional reinforced laminates due to off-axis matrix cracks is proposed and evaluated using data from fatigue experiments. Off-axis cracks are detected in images from the fatigue tests with automated crack detection to compute the crack density of the off-axis cracks which is used as the damage parameter for the degradation model. The purpose of this study is to test the effect of off-axis cracks on laminate stiffness for different laminate configurations. The hypothesis is that off-axis cracks have the same effect on the stiffness of a ply regardless of the acting stress components as long as the transverse stress is positive. This hypothesis proves to be wrong. The model is able to predict the stiffness degradation well for laminates with a ply orientation similar to the one used for calibration but deviates for plies with different in-plane shear stress. This behavior can be explained by the theory that off-axis cracks develop by two different micro damage modes depending on the level of in-plane shear stress. It is found that besides influencing the initiation and growth of off-axis cracks, the stiffness degradation is also mode dependent.

Influence of Increased Manganese Content on the Precipitation Behaviour of AISI H10 in Thermomechanical Fatigue Tests

2019 ◽  
pp. 189-196
Author(s):  
Serdal Acar ◽  
Oleksandr Golovko ◽  
Mark A. Swider ◽  
Florian Nuernberger ◽  
Martin Siegmund ◽  
...  
Keyword(s):  
Manganese Content ◽  
Thermomechanical Fatigue ◽  
Fatigue Tests ◽  
Precipitation Behaviour

Early stage crack detection in mechanically joined steel/aluminum joints by condition monitoring

2020 ◽  
Vol 62 (9) ◽  
pp. 877-882
Author(s):  
Maik Gollnick ◽  
P. Giese ◽  
D. Hein ◽  
G. Meschut ◽  
D. Herfert
Keyword(s):  
Condition Monitoring ◽  
Cyclic Load ◽  
Crack Detection ◽  
Early Stage ◽  
Failure Criteria ◽  
Fatigue Tests ◽  
Monitoring Systems ◽  
Pattern Recognition Methods ◽  
Condition Monitoring Systems ◽  
Acoustic Testing

Abstract Monitoring systems for machines, plants, materials and equipment are increasingly used in production processes. These online condition monitoring systems can detect damage or excessive loads at an early stage and can drastically reduce or prevent long downtimes of plants and machines as well as high repair and maintenance costs. This paper depicts a method for online crack detection with pattern recognition methods for specimens joined by self-pierce riveting under cyclic load in fatigue tests (laboratory application). A software specially conceived for this application was developed. This software, AnrissMF, uses active acoustic testing with a structure-borne sensor to detect cracks in the joints at a very early stage. It is shown in this paper that this software can detect cracks much earlier than classical failure criteria for joints (i. e. before any drop in stiffness or frequency is observed). Furthermore, the successful application of software AnrissMF for online crack detection during the fatigue strength test is presented.

The analysis and comparison of the RF and foreign standards for method of thermomechanical fatigue tests

2017 ◽  
pp. 11-11
Author(s):  
M.A. Gorbovets ◽  
◽  
D.A. Kochetkov ◽  
I.A. Khodinev ◽  
◽  
...  
Keyword(s):  
Thermomechanical Fatigue ◽  
Fatigue Tests

Improvement of Thermomechanical Fatigue Life in Nitrogen Alloyed 316 Stainless Steel

2005 ◽  
Vol 475-479 ◽  
pp. 1429-1432 ◽  
Author(s):  
Dae Whan Kim ◽  
Chang Hee Han ◽  
Woo Seog Ryu
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Temperature Change ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Thermomechanical Fatigue ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Phase Condition ◽  
Higher Temperature

Fatigue tests of type 316 and 316LN stainless steel were conducted at RT and 600ı, 0.8~1.5% strain range for low cycle fatigue (LCF), 300~600ı, 0% strain range for thermal fatigue (TF) and 300~600ı, 2% strain range, in-phase or out-of-phase for thermomechanical fatigue (TMF). LCF, TF, and TMF lives were increased but saturation stresses were decreased with the addition of nitrogen. The higher temperature was the lower TF life at a same temperature change. The minimum temperature change for TF failure was more than 100ı. TMF life was higher at inphase condition than at out-of-phase condition. Fracture mode was transgranular for LCF and outof- phase of TMF and almost transgranular and small intergranular for TF and in-phase TMF.

scholarly journals Crack Detection Zones: Computation and Validation

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2568
Author(s):  
Simon Pfingstl ◽  
Martin Steiner ◽  
Olaf Tusch ◽  
Markus Zimmermann
Keyword(s):  
Crack Detection ◽  
Strain Sensor ◽  
Fatigue Tests ◽  
Strain Sensors ◽  
Sensor Data ◽  
Detection Criterion ◽  
Minimum Number ◽  
Complete Failure ◽  
Relative Change ◽  
Strain Measures

During the development of aerospace structures, typically many fatigue tests are conducted. During these tests, much effort is put into inspections in order to detect the onset of failure before complete failure. Strain sensor data may be used to reduce inspection effort. For this, a sufficient number of sensors need to be positioned appropriately to collect the relevant data. In order to minimize cost and effort associated with sensor positioning, the method proposed here aims at minimizing the number of necessary strain sensors while positioning them such that fatigue-induced damage can still be detected before complete failure. A suitable detection criterion is established as the relative change of strain amplitudes under cyclic loading. Then, the space of all possible crack lengths is explored. The regions where the detection criterion is satisfied before complete failure occurs are assembled into so-called detection zones. One sensor in this zone is sufficient to detect criticality. The applicability of the approach is demonstrated on a representative airplane structure that resembles a lower wing section. The method shows that four fatigue critical spots can be monitored using only one strain sensor in a non-intuitive position. Furthermore, we discuss two different strain measures for crack detection. The results of this paper can be used for reliable structural health monitoring using a minimum number of sensors.

Sign in / Sign up

Export Citation Format

Share Document