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strain amplitude

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Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002356
EISBN: 978-1-62708-193-1
... consider a notched specimen. An obvious question then is why microcracks are not nucleated in all grains. Actually, if the strain amplitude at the surface is large, microscopic investigations have shown that there will be a high number of microcracks in Al alloys ( Ref 1 , 2 , 3 ). Due to the low elastic...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002354
EISBN: 978-1-62708-193-1
.... For many years, and especially since the work of Coffin ( Ref 5 ) and Manson ( Ref 6 ), it has been known and well-accepted that fatigue failure has to be attributed to repeated cyclic plastic straining. The stress amplitudes leading to fatigue failure are in most cases too small to cause “macro-yielding...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002366
EISBN: 978-1-62708-193-1
... explained, including mean stress effects, sequences of stress/strain amplitude or stress state, nonproportional loading and cycle counting, and HCF fatigue limits. In addition, the article covers the formation and propagation of cracks on the order of several grain sizes in diameter in initially isotropic...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003294
EISBN: 978-1-62708-176-4
... Abstract This article reviews high strain rate compression and tension test methods with a focus on the general principles, advantages, and limitations of each test method. The compression test methods are cam plastometer test, drop tower compression test, the Hopkinson bar in compression...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003295
EISBN: 978-1-62708-176-4
... that becomes greater with a shorter pulse and larger amplitude. This results in a short-pulse radial stress component in the specimen superposed on the axial stress component. Hence, in axial loading, the state of stress in the specimen is only at constant strain rates. In torsional testing, however...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002398
EISBN: 978-1-62708-193-1
... size, defect size, stress modes, and waveform types. The article discusses various fracture mechanics in cast steels: cyclic stress-strain behavior and low- and high-cycle fatigue life behavior; plane-stress fracture toughness; plane-strain fracture toughness; constant-amplitude fatigue crack...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002364
EISBN: 978-1-62708-193-1
... and are called fatigue properties. The reader is also referred to “Recommended Practice for Strain Controlled Fatigue Testing,” ASTM E606-92, for the methodology involved in performing such tests. Determination of constant-amplitude fatigue lives of specimens is customarily performed under conditions...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002365
EISBN: 978-1-62708-193-1
... on their manner of use and limitations. The use of the Palmgren-Miner rule for life prediction for variable amplitude loading is also discussed. fatigue life Palmgren-Miner rule strain-based approach stress-based approach variable amplitude load FATIGUE LIFE ESTIMATES are often needed in engineering...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003315
EISBN: 978-1-62708-176-4
... ) These extremely high frequencies surpass the upper limits of practicality because of the constraints of specimen size (frequency is inversely proportional to specimen length), machining tolerances, strain amplitude measurements, and energy considerations. A review of the ultrasonic fatigue testing in the 1970s...
Series: ASM Handbook
Volume: 2B
Publisher: ASM International
Published: 15 June 2019
DOI: 10.31399/asm.hb.v02b.a0006549
EISBN: 978-1-62708-210-5
...) or plastic (low cycle), which in turn depends on the properties of the metal as well as the magnitude of the nominal stress. The elastic and plastic strain components for an S - N curve are illustrated in Fig. 18 . Fig. 18 Representation of total strain amplitude (Δε t /2) vs. number of reversals...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002353
EISBN: 978-1-62708-193-1
... due to a sufficiently high alternating plastic strain amplitude. When a dislocation emerges at the surface, a slip step of one Burgers vector is created. During perfect reversed loading on the same slip plane, this step is canceled; however, slip occurs on many planes, and the reversal is never...
Series: ASM Handbook
Volume: 1
Publisher: ASM International
Published: 01 January 1990
DOI: 10.31399/asm.hb.v01.a0001038
EISBN: 978-1-62708-161-0
... amplitude (half the strain range). During cyclic loading, the stress-strain relationship can usually be described by a loop, such as that shown in Fig. 9 . For purely elastic loading, the loop becomes a straight line whose slope is the elastic modulus, E , of the material. The occurrence...
Series: ASM Handbook
Volume: 20
Publisher: ASM International
Published: 01 January 1997
DOI: 10.31399/asm.hb.v20.a0002469
EISBN: 978-1-62708-194-8
... changed very little when measured on a per cycle basis. The fully cold-worked specimen, hysteresis loops on the right, cyclically softens, and the stress range decreases. The tests depicted in Fig. 15 were done in strain control. The strain amplitude was kept constant. All other quantities...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0005723
EISBN: 978-1-62708-193-1
... minimum plastic strain ε pl,s plastic strain amplitude of saturation ε th thermal strain rate Δε strain range Δε,Δε net net strain range Δε/2 strain amplitude Δε e /2 elastic strain amplitude Δε m ,Δε mech mechanical strain range Δε p /2 plastic strain...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002355
EISBN: 978-1-62708-193-1
... 6 ). In macroscopically inhomogeneous materials, such as surface hardened steels, cracks often start below the surface where constraint effects induce high triaxial stresses. For the same plastic strain amplitude in the surface layer, a much higher stress is required in comparison to the softer...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0009219
EISBN: 978-1-62708-176-4
.... This scatter can cause the results of a fatigue test program to be confusing if the test matrix is not well designed and the results are not evaluated in an appropriate statistical manner. Fatigue testing usually is performed to estimate the relationship between the amplitude of stress or strain (or load...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002350
EISBN: 978-1-62708-193-1
... Fig. 10 Representation of total strain amplitude vs. number of reversals to failure, including elastic and plastic portions as well as the combined curve N t , transition life from plastic (low-cycle) regime to the elastic (high-cycle) regime Fig. 11 Schematic representation...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003318
EISBN: 978-1-62708-176-4
...; in general, polymers are more sensitive to the testing environment than metal or ceramic counterparts. These variables include the stress or strain amplitude of the loading cycle; the mean stress of the cycle; the presence of stress concentrations or initial defects in the component; the frequency...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003314
EISBN: 978-1-62708-176-4
... testing specimen machining surface preparation gripping system THE FATIGUE CRACK INITIATION RESISTANCE of an alloy is determined by conducting a series of tests over a range of values of stress amplitude or strain range. The observed number of cycles to failure is plotted against the stress...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002396
EISBN: 978-1-62708-193-1
...-law hardening relation between strain amplitude, ε a , and stress amplitude, σ a , as is often used for monotonic curves: (Eq 1) ε a = σ a E + ( σ a K ′ ) 1 / n ′ where E is the elastic modulus and K ′ and n ′ are cyclic deformation properties...