Effects of frequency on fatigue behavior of CVI C/SiC at elevated temperature

2006 ◽  
Vol 66 (7-8) ◽  
pp. 863-874 ◽  
Author(s):  
Shankar Mall ◽  
John Mark Engesser
Keyword(s):  
Elevated Temperature ◽  
Fatigue Behavior

scholarly journals Thermal Stability of Residual Stresses in Differently Deep Rolled Surface Layers of Steel SAE 1045

2021 ◽  
Author(s):  
Stephanie Saalfeld ◽  
Thomas Wegener ◽  
Berthold Scholtes ◽  
Thomas Niendorf
Keyword(s):  
Thermal Stability ◽  
Elevated Temperature ◽  
Residual Stresses ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Decisive Role ◽  
Deep Rolling ◽  
Material Conditions ◽  
The Stability ◽  
Thermal Stability Of

AbstractThe stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and time on the relaxation behavior of residual stresses at elevated temperature. To evaluate the effect of deep rolling at elevated temperatures on stability limits under thermal as well as combined thermo-mechanical loads, the present work introduces and discusses the results of investigations on the thermal stability of residual stresses in differently deep rolled material conditions of the steel SAE 1045.

Isothermal Fatigue Behavior and Damage Modeling of a High Temperature Woven PMC

1999 ◽  
Vol 122 (1) ◽  
pp. 62-68 ◽  
Author(s):  
A. L. Gyekenyesi
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Stiffness Degradation ◽  
Fatigue Properties ◽  
Residual Compressive Strength ◽  
Stiffness Reduction ◽  
Fatigue Damage Accumulation ◽  
Strength Tests

This study focuses on the fully reversed fatigue behavior exhibited by a carbon fiber/polyimide resin woven laminate at room and elevated temperatures. Nondestructive video edge view microscopy and destructive sectioning techniques were used to study the microscopic damage mechanisms that evolved. The elastic stiffness was monitored and recorded throughout the fatigue life of the coupon. In addition, residual compressive strength tests were conducted on fatigue coupons with various degrees of damage as quantified by stiffness reduction. Experimental results indicated that the monotonic tensile properties were only minimally influenced by temperature, while the monotonic compressive and fully reversed fatigue properties displayed greater reductions due to the elevated temperature. The stiffness degradation, as a function of cycles, consisted of three stages; a short-lived high degradation period, a constant degradation rate segment covering the majority of the life, and a final stage demonstrating an increasing rate of degradation up to failure. Concerning the residual compressive strength tests at room and elevated temperatures, the elevated temperature coupons appeared much more sensitive to damage. At elevated temperatures, coupons experienced a much larger loss in compressive strength when compared to room temperature coupons with equivalent damage. The fatigue damage accumulation law proposed for the model incorporates a scalar representation for damage, but admits a multiaxial, anisotropic evolutionary law. The model predicts the current damage (as quantified by residual stiffness) and remnant life of a composite that has undergone a known load at temperature. The damage/life model is dependent on the applied multiaxial stress state as well as temperature. Comparisons between the model and data showed good predictive capabilities concerning stiffness degradation and cycles to failure. [S0742-4795(00)01001-2]

Low cycle fatigue behavior of nickel-based superalloy GH4145/SQ at elevated temperature

2004 ◽  
Vol 373 (1-2) ◽  
pp. 54-64 ◽  
Author(s):  
Duyi Ye ◽  
Dehai Ping ◽  
Zhenlin Wang ◽  
Haohao Xu ◽  
Xiaoyu Mei ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Nickel Based Superalloy

Life Prediction of Stainless Steels under Creep-Fatigue

2009 ◽  
Vol 413-414 ◽  
pp. 725-732 ◽  
Author(s):  
Xiao Cong He
Keyword(s):  
Stainless Steel ◽  
Elevated Temperature ◽  
Test Data ◽  
Stainless Steels ◽  
Life Prediction ◽  
Prediction Models ◽  
Fatigue Behavior ◽  
Summation Method ◽  
Tensile Creep ◽  
Creep Fatigue

The aim of this study is to investigate the creep-fatigue behavior of stainless steel materials. Based on the elevated-temperature tensile, creep and rupture test data, thermal creep-fatigue modelling was conducted to predict the failure life of stainless steels. In the low cycle thermal fatigue life model, Manson’s Universal Slopes equation was used as an empirical correlation which relates fatigue endurance to tensile properties. Fatigue test data were used in conjunction with different modes to establish the relationship between temperature and other parameters. Then creep models were created for stainless steel materials. In order to correlate the results of short-time elevated temperature tests with long-term service performance at more moderate temperatures, different creep prediction models, namely Basquin model, Sherby-Dorn model and Manson-Haferd model, were studied. Comparison between the different creep prediction models were carried out for a range of stresses and temperatures. A linear damage summation method was used to establish life prediction model of stainless steel materials under creep-fatigue.

Cyclic Softening Effect on Design Margin of JLF-1 Steel

2013 ◽  
Author(s):  
Huailin Li
Keyword(s):  
Elevated Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cyclic Softening ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Softening Effect ◽  
As Stress ◽  
Supercritical Water Cooled Reactor ◽  
Design Margin

A reduced-activation ferritic/martensitic (RAF/M) steel, JLF-1, is considered as one of the candidate structure material of the fusion reactors and supercritical water-cooled reactor (SCWR). Low cycle fatigue properties of JLF-1 steel at elevated temperature are the design base to provide adequate design margin against postulated mechanism that could experience during its design life, such as stress range, plastic deformation, and cyclic softening etc. However, the reduction in design margin is significant when the cyclic softening happens in cyclic deformation at RT, 673K, 873K. Thus, for the application as the structural materials, it is necessary to evaluate low cycle fatigue behavior and cyclic softening of JLF-1 steel at elevated temperature since those properties of material at elevated temperature are the key issue for design.

Grade 11 High Temperature Steam Header Case History and Benchmark

2016 ◽  
Author(s):  
Dave Dewees
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Method Validation ◽  
Case History ◽  
Design Method ◽  
Fatigue Behavior ◽  
Method Performance ◽  
Elevated Temperature Design ◽  
High Temperature Steam ◽  
Grade 11

The cost and complexity of design method validation at the component level makes actual and comprehensive benchmark cases challenging to obtain. This is especially true of elevated temperature design methods where component and material response is complicated by time-dependent creep and possibly creep-fatigue behavior. To support current Design-by-Analysis modernization development within Section I of the ASME Boiler & Pressure Vessel Code, service examples that are comprehensive enough to allow method validation, while still being tractable in complexity have been identified. To this end, the case history of a Grade 11 high temperature steam outlet header that was retired after 23 of years of service is presented. Detailed damage and deformation information is available which allows validation of creep material models, as well as future evaluation of candidate elevated temperature design method performance.

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