The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Pete Starke - One of the best experts on this subject based on the ideXlab platform.
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a unified Fatigue Life Calculation based on intrinsic thermal dissipation and microplasticity evolution
International Journal of Fatigue, 2020Co-Authors: Pete Starke, Zhenjie Teng, Christia OlleAbstract:Abstract This paper advances a unified approach by evaluating the evolution of the intrinsic thermal dissipation and the microplasticity strain amplitude of SAE1045 steel. The intrinsic dissipation is utilized to understand the Fatigue behavior and to link the materials’ microstructure evolution directly. The microplasticity strain amplitude is related to a Fatigue process and correlated to Fatigue Life that can be deducted from the change in temperature. With only one load increase test and one constant amplitude test in the present case, an S-N curve can be evaluated being in very good agreement with experimentally determined data obtained the traditional way.
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phybal a short time procedure for a reliable Fatigue Life Calculation
Advanced Engineering Materials, 2010Co-Authors: Pete Starke, Frank Walthe, Dietma EifleAbstract:IntroductionFor reliable and cost-effective Fatigue Life Calculations ofmetallic materials a systematic investigation of their cyclicdeformation behaviour and a comprehensive understandingof the underlying Fatigue mechanisms are mandatory. Inparticular, the Fatigue properties are strongly influenced bythe heat treatment condition of the investigated material. Forexample, the cyclic deformation behaviour can vary betweenpure cyclic softening, cyclic softening followed by cyclichardening or pure cyclic hardening. In general higher plasticstrains lead to a reduction of Fatigue Life.In this paper, the physically based Fatigue Life Calculationmethod ‘‘PHYBAL’’ was developed for the short-timeCalculation of S-N (Woehler) curves of metallic materials.With ‘‘PHYBAL’’, the S-N curves of different metals or heattreatmentconditionscanbecalculatedonthebasisofonlyoneload increase test and two constant amplitude tests.‘‘PHYBAL’’ was applied for the steel SAE 4140 (42CrMo4)in four heat treatment conditions (quenched and tempered,normalised, bainitic and quenched) and the calculatedLifetimes were verified in detail in conventional constantamplitude tests.For the detailed description and evaluation of the materialresponse to cyclic loading the plastic strain amplitude
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new Fatigue Life Calculation method for quenched and tempered steel sae 4140
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Pete Starke, Frank Walthe, Dietma EifleAbstract:Abstract In stress-controlled constant amplitude and service loading tests at ambient temperature mechanical stress-strain hysteresis, temperature and electrical resistance measurements were performed to characterize the Fatigue behavior of the quenched and tempered steel SAE 4140. The applied measurement methods use deformation-induced changes of the microstructure in the bulk material and represent the actual Fatigue state. A new test procedure combines any kind of load spectra with periodically inserted constant amplitude sequences to measure the plastic strain amplitude, the change in temperature and the change in electrical resistance at the same time. The average values of the measuring sequences are plotted as function of the number of cycles in cyclic ‘deformation’ curves and represent the summation of microstructural changes caused by service loading. On the basis of generalized Morrow and Basquin equations the physically based Fatigue Life Calculation method “PHYBAL” was developed for constant amplitude and service loading. With only three Fatigue tests, Woehler (S–N) and Fatigue Life curves can be calculated in very good agreement with experimental ones determined in a conventional manner. The application of “PHYBAL” provides an enormous saving of experimental time and costs.
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Fatigue assessment and Fatigue Life Calculation of metals on the basis of mechanical hysteresis temperature and resistance data
Materials Testing-Materials and Components Technology and Application, 2009Co-Authors: Pete Starke, Dietma EifleAbstract:AbstractMechanical stress-strain hysteresis, temperature, and electrical resistance measurements were performed for the microstructurerelated characterisation of the cyclic deformation behaviour and for the Fatigue Life Calculation of metals. The electrical resistance is strongly influenced by the defect density, and allows the detection of a proceeding Fatigue damage under cyclic loading and during load-free inspection intervals as well. On the basis of comprehensive mechanical, thermal, and electrical Fatigue data the physically based Fatigue Life Calculation “Phybal” was developed at the Institute of Materials Science and Engineering at the University of Kaiserslautern. This method requires only one load increase test and two constant amplitude tests for a fast and nevertheless precise Calculation of S-N (Woehler) curves, leading to a significant reduction in experimental time and costs.
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Fatigue assessment and Fatigue Life Calculation of quenched and tempered sae 4140 steel based on stress strain hysteresis temperature and electrical resistance measurements
Fatigue & Fracture of Engineering Materials & Structures, 2007Co-Authors: Pete Starke, Frank Walthe, Dietma EifleAbstract:In this paper, mechanical stress–strain-hysteresis, temperature and electrical resistance measurements are performed for the detailed characterization of the Fatigue behaviour of quenched and tempered SAE 4140 steel used for many applications in the automotive industry. Stress-controlled load increase and constant amplitude tests (CATs) were carried out at ambient temperature on servo-hydraulic testing systems. The applied measurement methods depend on deformation-induced changes of the microstructure in the bulk material and represent the actual Fatigue state. The plastic strain amplitude, the change in temperature and the change in electrical resistance can be equally used for an assessment of baseline Fatigue properties in generalized cyclic deformation curves as well as in generalized Morrow and Coffin–Manson curves. On the basis of comprehensive experimental Fatigue data, the physically based Fatigue Life Calculation method ‘PHYBAL’ based on the generalized Basquin equation was developed. S–N (Woehler) curves calculated with ‘PHYBAL’ using data from only three Fatigue tests agree very well with the conventionally determined ones.
Dietma Eifle - One of the best experts on this subject based on the ideXlab platform.
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phybalsit Fatigue assessment and Life time Calculation of the ductile cast iron en gjs 600 at ambient and elevated temperatures
Characterization of Minerals Metals and Materials, 2015Co-Authors: Enjami Jos, Marcus Klei, Dietma EifleAbstract:This paper focuses on the ductile cast iron EN-GJS-600 which is often used for components of combustion engines. Under service conditions, those components are mechanically loaded at different temperatures. Therefore, this investigation targets at the Fatigue behavior of EN-GJS-600 at ambient and elevated temperatures. Light and scanning electron microscopic investigations were done to characterize the sphericity of the graphite as well as the ferrite, pearlite and graphite fraction. At elevated temperatures, the consideration of dynamic strain ageing effects is of major importance. In total strain increase, temperature increase and constant total strain amplitude tests, the plastic strain amplitude, the stress amplitude, the change in temperature and the change in electrical resistance were measured. The measured values depend on plastic deformation processes in the bulk of the specimens and at the interfaces between matrix and graphite. The Fatigue behavior of EN-GJS-600 is dominated by cyclic hardening processes. The physically based Fatigue Life Calculation “PHYBALSIT” (SIT = strain increase test) was developed for total strain controlled Fatigue tests. Only one temperature increase test is necessary to determine the temperature interval of pronounced dynamic strain ageing effects.
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Fatigue Life Calculation of metastable austenitic steels
ICF12 Ottawa 2009, 2013Co-Authors: Marek Smaga, Frank Walthe, Dietma EifleAbstract:Monotonic and cyclic Plastic deformation of metastable austenitic steels can lead to a phase transformation from paramagnetic austenite to ferromagnetic α´- martensite. The deformation-induced changes of the magnetic properties are directly related to the accumulated plastic strain and therefore to the actual Fatigue state. This paper includes a detailed characterization of the deformation-induced austenite-martensite-transformation in the metastable austenitic steels AISI 304, AISI 321 and AISI 348. The cyclic deformation behavior is evaluated by mechanical stress-strain hysteresis as well as high-precision temperature measurements. With in-situ ferritescope magnetic measurements, the development of the α´-martensite and the change in the magnetic induction due to the Villari effect were investigated. On the basis of far-reaching cross effects of mechanical and magnetic properties, measurements of magnetic-mechanical hysteresis loops were performed. Hence, a method for Fatigue Life Calculation based on the change in magnetic properties has been developed.
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phybal a short time procedure for a reliable Fatigue Life Calculation
Advanced Engineering Materials, 2010Co-Authors: Pete Starke, Frank Walthe, Dietma EifleAbstract:IntroductionFor reliable and cost-effective Fatigue Life Calculations ofmetallic materials a systematic investigation of their cyclicdeformation behaviour and a comprehensive understandingof the underlying Fatigue mechanisms are mandatory. Inparticular, the Fatigue properties are strongly influenced bythe heat treatment condition of the investigated material. Forexample, the cyclic deformation behaviour can vary betweenpure cyclic softening, cyclic softening followed by cyclichardening or pure cyclic hardening. In general higher plasticstrains lead to a reduction of Fatigue Life.In this paper, the physically based Fatigue Life Calculationmethod ‘‘PHYBAL’’ was developed for the short-timeCalculation of S-N (Woehler) curves of metallic materials.With ‘‘PHYBAL’’, the S-N curves of different metals or heattreatmentconditionscanbecalculatedonthebasisofonlyoneload increase test and two constant amplitude tests.‘‘PHYBAL’’ was applied for the steel SAE 4140 (42CrMo4)in four heat treatment conditions (quenched and tempered,normalised, bainitic and quenched) and the calculatedLifetimes were verified in detail in conventional constantamplitude tests.For the detailed description and evaluation of the materialresponse to cyclic loading the plastic strain amplitude
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new Fatigue Life Calculation method for quenched and tempered steel sae 4140
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Pete Starke, Frank Walthe, Dietma EifleAbstract:Abstract In stress-controlled constant amplitude and service loading tests at ambient temperature mechanical stress-strain hysteresis, temperature and electrical resistance measurements were performed to characterize the Fatigue behavior of the quenched and tempered steel SAE 4140. The applied measurement methods use deformation-induced changes of the microstructure in the bulk material and represent the actual Fatigue state. A new test procedure combines any kind of load spectra with periodically inserted constant amplitude sequences to measure the plastic strain amplitude, the change in temperature and the change in electrical resistance at the same time. The average values of the measuring sequences are plotted as function of the number of cycles in cyclic ‘deformation’ curves and represent the summation of microstructural changes caused by service loading. On the basis of generalized Morrow and Basquin equations the physically based Fatigue Life Calculation method “PHYBAL” was developed for constant amplitude and service loading. With only three Fatigue tests, Woehler (S–N) and Fatigue Life curves can be calculated in very good agreement with experimental ones determined in a conventional manner. The application of “PHYBAL” provides an enormous saving of experimental time and costs.
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Fatigue Life Calculation of metastable austenitic stainless steels on the basis of magnetic measurements
Materials Testing-Materials and Components Technology and Application, 2009Co-Authors: Marek Smaga, Dietma EifleAbstract:Abstract Monotonic and cyclic plastic deformation of metastable austenitic steels lead to a phase transformation from paramagnetic austenite into ferromagnetic α′-martensite. The deformation-induced changes of the magnetic properties are directly related to the accumulated plastic strain and therefore to the actual Fatigue state. This paper includes a detailed characterization of the deformation-induced austenite-martensite-transformation in metastable austenitic steels. The cyclic deformation behaviour was evaluated by mechanical stress-strain hysteresis and temperature measurements. With in-situ Ferritescope magnetic measurements, the development of the α′-martensite, and the change in the magnetic induction due to the Villari effect were investigated. On the basis of far-reaching cross effects of mechanical and magnetic properties, measurements of magnetic-mechanical hysteresis loops were performed. Hence a method for Fatigue Life Calculation based on the change in magnetic properties was developed.
Frank Walthe - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Life Calculation of metastable austenitic steels
ICF12 Ottawa 2009, 2013Co-Authors: Marek Smaga, Frank Walthe, Dietma EifleAbstract:Monotonic and cyclic Plastic deformation of metastable austenitic steels can lead to a phase transformation from paramagnetic austenite to ferromagnetic α´- martensite. The deformation-induced changes of the magnetic properties are directly related to the accumulated plastic strain and therefore to the actual Fatigue state. This paper includes a detailed characterization of the deformation-induced austenite-martensite-transformation in the metastable austenitic steels AISI 304, AISI 321 and AISI 348. The cyclic deformation behavior is evaluated by mechanical stress-strain hysteresis as well as high-precision temperature measurements. With in-situ ferritescope magnetic measurements, the development of the α´-martensite and the change in the magnetic induction due to the Villari effect were investigated. On the basis of far-reaching cross effects of mechanical and magnetic properties, measurements of magnetic-mechanical hysteresis loops were performed. Hence, a method for Fatigue Life Calculation based on the change in magnetic properties has been developed.
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phybal a short time procedure for a reliable Fatigue Life Calculation
Advanced Engineering Materials, 2010Co-Authors: Pete Starke, Frank Walthe, Dietma EifleAbstract:IntroductionFor reliable and cost-effective Fatigue Life Calculations ofmetallic materials a systematic investigation of their cyclicdeformation behaviour and a comprehensive understandingof the underlying Fatigue mechanisms are mandatory. Inparticular, the Fatigue properties are strongly influenced bythe heat treatment condition of the investigated material. Forexample, the cyclic deformation behaviour can vary betweenpure cyclic softening, cyclic softening followed by cyclichardening or pure cyclic hardening. In general higher plasticstrains lead to a reduction of Fatigue Life.In this paper, the physically based Fatigue Life Calculationmethod ‘‘PHYBAL’’ was developed for the short-timeCalculation of S-N (Woehler) curves of metallic materials.With ‘‘PHYBAL’’, the S-N curves of different metals or heattreatmentconditionscanbecalculatedonthebasisofonlyoneload increase test and two constant amplitude tests.‘‘PHYBAL’’ was applied for the steel SAE 4140 (42CrMo4)in four heat treatment conditions (quenched and tempered,normalised, bainitic and quenched) and the calculatedLifetimes were verified in detail in conventional constantamplitude tests.For the detailed description and evaluation of the materialresponse to cyclic loading the plastic strain amplitude
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new Fatigue Life Calculation method for quenched and tempered steel sae 4140
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Pete Starke, Frank Walthe, Dietma EifleAbstract:Abstract In stress-controlled constant amplitude and service loading tests at ambient temperature mechanical stress-strain hysteresis, temperature and electrical resistance measurements were performed to characterize the Fatigue behavior of the quenched and tempered steel SAE 4140. The applied measurement methods use deformation-induced changes of the microstructure in the bulk material and represent the actual Fatigue state. A new test procedure combines any kind of load spectra with periodically inserted constant amplitude sequences to measure the plastic strain amplitude, the change in temperature and the change in electrical resistance at the same time. The average values of the measuring sequences are plotted as function of the number of cycles in cyclic ‘deformation’ curves and represent the summation of microstructural changes caused by service loading. On the basis of generalized Morrow and Basquin equations the physically based Fatigue Life Calculation method “PHYBAL” was developed for constant amplitude and service loading. With only three Fatigue tests, Woehler (S–N) and Fatigue Life curves can be calculated in very good agreement with experimental ones determined in a conventional manner. The application of “PHYBAL” provides an enormous saving of experimental time and costs.
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Fatigue assessment and Fatigue Life Calculation of quenched and tempered sae 4140 steel based on stress strain hysteresis temperature and electrical resistance measurements
Fatigue & Fracture of Engineering Materials & Structures, 2007Co-Authors: Pete Starke, Frank Walthe, Dietma EifleAbstract:In this paper, mechanical stress–strain-hysteresis, temperature and electrical resistance measurements are performed for the detailed characterization of the Fatigue behaviour of quenched and tempered SAE 4140 steel used for many applications in the automotive industry. Stress-controlled load increase and constant amplitude tests (CATs) were carried out at ambient temperature on servo-hydraulic testing systems. The applied measurement methods depend on deformation-induced changes of the microstructure in the bulk material and represent the actual Fatigue state. The plastic strain amplitude, the change in temperature and the change in electrical resistance can be equally used for an assessment of baseline Fatigue properties in generalized cyclic deformation curves as well as in generalized Morrow and Coffin–Manson curves. On the basis of comprehensive experimental Fatigue data, the physically based Fatigue Life Calculation method ‘PHYBAL’ based on the generalized Basquin equation was developed. S–N (Woehler) curves calculated with ‘PHYBAL’ using data from only three Fatigue tests agree very well with the conventionally determined ones.
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Fatigue Life Calculation of sae 1050 and sae 1065 steel under random loading
International Journal of Fatigue, 2007Co-Authors: Frank Walthe, Dietma EifleAbstract:Abstract In this investigation, stress-controlled Fatigue tests with SAE 1050 and SAE 1065 specimens were performed under single step and random loading to study Fatigue mechanisms with particular attention to microstructural details. The applied plastic strain amplitude, temperature and electrical resistance measurements depend on deformation-induced changes of the microstructure and represent the actual Fatigue state of the investigated steels. A new test procedure combines any kind of load spectra with periodically inserted single step sequences to measure the plastic strain amplitude, the temperature and the electrical resistance. The average values of the measuring sequences are plotted as function of the number of cycles in cyclic ‘deformation’ curves and represent the summation of microstructural changes caused by random loading. Electrical resistance measurements allow to detect the proceeding Fatigue damage even in the load-free state. On the basis of comprehensive experimental Fatigue data the physically based Lifetime Calculation method “PHYBAL” using generalized Morrow, Coffin–Manson and Basquin equations was developed for single step and random loading. S–N (Woehler) curves calculated with “PHYBAL” agree very well with experimentally determined Lifetimes.
Aleksander Karolczuk - One of the best experts on this subject based on the ideXlab platform.
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analysis of revised Fatigue Life Calculation algorithm under proportional and non proportional loading with constant amplitude
International Journal of Fatigue, 2016Co-Authors: Aleksander KarolczukAbstract:Abstract This paper reports the results of a study into a revised algorithm applied to the Fatigue Life Calculation under cyclic multiaxial proportional and non-proportional loading. In contrast to the classical algorithm, which assumes that material parameters in the Fatigue criterion are constant, the revised algorithm relates the values of these parameters to the number of cycles to failure. The objectives in this paper include verification of the convergence for the revised algorithm and evaluation of the Fatigue Life Calculation by use of the revised algorithm. Detailed implementations of the multiaxial Fatigue criteria by Matake and Papadopoulos are presented for the algorithm. The calculated Fatigue lives are compared to the experimental ones for three steel grades: SAE1045, S355J2G and SM45C subjected to cyclic uniaxial and multiaxial proportional and non-proportional loading. It is shown that the revised algorithm provides a sole solution under the proportional and non-proportional loading by application of the Matake and Papadopoulos criteria. A higher convergence between experimental and calculated Fatigue Life is obtained for the revised algorithm than for the classical one.
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a correction in the algorithm of Fatigue Life Calculation based on the critical plane approach
International Journal of Fatigue, 2016Co-Authors: Aleksander Karolczuk, Krzysztof Kluger, Tadeusz ŁagodaAbstract:Abstract The paper presents the algorithm for calculating the Fatigue Life taking into account the variability of coefficients occurring in the multiaxial Fatigue criterion depending on the number of cycles to failure. The algorithm has been analysed under uniaxial cyclic loads and a combination of bending and torsion for four structural materials. Significant increase of convergence of calculated and experimental Fatigue Life using the new algorithm as compared to the classical approach for five selected multiaxial Fatigue criteria based on a critical plane has been demonstrated.
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selection of the critical plane orientation in two parameter multiaxial Fatigue failure criterion under combined bending and torsion
Engineering Fracture Mechanics, 2008Co-Authors: Aleksander Karolczuk, Ewald MachaAbstract:Abstract The present paper is focused on engineering application of the algorithm of Fatigue Life Calculation under multiaxial Fatigue loading. For that reason, simple two-parameter multiaxial Fatigue failure criterion is proposed. The criterion is based on the normal and shear stresses on the critical plane. Experimental results obtained under multiaxial proportional, non-proportional cyclic loading and variable-amplitude bending and torsion were used to verify the proposed two-parameter criterion and other well-known multiaxial Fatigue criteria. Elastic–plastic behaviour of the bulk material was taken into account in Calculation of the stress/strain distribution across the specimen cross-section. It is shown that the proposed two-parameter multiaxial Fatigue failure criterion gives the best correlation between the experimental and calculated Fatigue lives.
Tao Wu - One of the best experts on this subject based on the ideXlab platform.
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a damage model based on the critical plane to estimate Fatigue Life under multi axial random loading
International Journal of Fatigue, 2019Co-Authors: Tao WuAbstract:Abstract A multi-axial random vibration Fatigue damage parameter was proposed based on a critical plane damage parameter for multi-axial high cycle Fatigue, which is an equivalent stress power spectral density (PSD). The Fatigue Life Calculation under multi-axial random loading could be conducted based on the equivalent stress PSD, combined with the spectral method under uniaxial random loading. The multi-axial random vibration Fatigue experiment was conducted on the thin-walled circular tube with slots on the side. The Fatigue Life results obtained from the experiment were compared with the ones calculated from the proposed model, which indicated that the proposed parameter did a good job in predicting the multi-axial random vibration Fatigue Life.
