Automatic procedure for evaluating the Paris Law of martensitic and austenitic stainless steels by means of thermal methods

Ancona, F.; Palumbo, Davide; Finis, Rosa De; Demelio, G.; Galietti, Umberto

doi:10.1016/j.engfracmech.2016.06.016

Cited by 38 publications

(34 citation statements)

References 28 publications

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“…The standard [17] reports also, the test execution procedure. In particular, a constant-force-amplitude procedure was applied, the constant force range was ΔP=10.8 kN, the stress ratio was R=0.1 and loading frequency was 13 Hz.…”

Section: Methodsmentioning

confidence: 99%

“…In fact, the assessment of sum of the stress in principal directions it is possible to full characterize the SIF while the analysis of the thermoelastic phase data allows for crack growth rate determination. In this regard, Ancona et al [13] proposed an automatic procedure based on TSA, to assess the Paris Law constants and to study the fracture behavior of four stainless steels.…”

Section: Introductionmentioning

confidence: 99%

“…In the specific field of fracture mechanics, a temperature rise is detected in the plastic zone around the crack tip where the plastic volume dissipates energy [9][10][11][12]. Therefore, thermography represents a valid tool to localise the crack tip that is important for both determining in experimental way, the Paris Law [13] as well as fatigue crack propagation [14].…”

Section: Introductionmentioning

confidence: 99%

“…The first authors that, proposed a relation between crack growth rate and stress intensity factor (SIF) were Paris and Erdogan [15][16] The Standards [17] provide conventional methods to assess the constants of Paris's Law by means of experimental non-destructive techniques [1], [11][12][13] [18].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Energetic approach to study the plastic behaviour in CT specimens

Finis¹,

Palumbo²,

Galietti³

2018

Proceedings of the 2018 International Conference on Quantitative InfraRed Thermography

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Thermography is very useful for characterising fracture mechanics behaviour of stainless steels. In this work, the technique is proposed for evaluating the intrinsic dissipations occurring in the plastic area around the crack tip in order to study the fatigue crack growth.The existing experimental techniques involve accurate equipment and setup for assessing an estimation of the energy dissipated ahead the crack tip, in this way such the usability of these methods is restricted to just laboratory tests. Otherwise, the use of thermography based approach allows accurate analysis of energy variation occurring in a very localised area of the material. In particular, the adopted approach is based on thermal signal investigation in the frequency domain for separating the temperature values related to energy of dissipative processes that occur at twice the loading frequency.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Energetic approach to study the plastic behaviour in CT specimens

Finis¹,

Palumbo²,

Galietti³

2018

Proceedings of the 2018 International Conference on Quantitative InfraRed Thermography

Self Cite

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“…The thermography is actually used in the hot stamping industry to detect cooling issues in the part and/or tool normally caused by cooling channel clogging, leakage, water supply shortage, etc. [11], and in other applications [14]. This technique is useful to understand the process without contact with the material.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Martensitic Transformation on the Stamping Force and Cycle Time of Hot Stamping Parts

Muro

Artola

Gorriño

et al. 2018

Metals

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Abstract:Stamping dies perform two functions in the hot stamping process of body-in-white components. Firstly, they form the steel sheet into the desired shape and, secondly, they quench the steel at a cooling rate that leads to hardening by means of the austenite-γ to martensite transformation. This microstructural change implies a volume expansion that should lead to a force peak in the press, which has yet to be detected in industrial practice. In this study, a set of hot stamping laboratory tests were performed on instrumented Al-Si-coated 22MnB5 steel flat formats to analyze the effect of the stamping pressure on the detection of the expected peak. Plotting the sheet temperature and pressure curves against time allowed us to identify and understand the conditions in which the force peak can be detected. These conditions occurred most favorably when the stamping pressure is below 5 MPa. It is thus possible to determine the exact moment at which the complete hardening transformation occurs by monitoring the local pressing force of the tool in areas where the pressure exerted on the metal format is below 5 MPa. This information can be applied to optimize the time needed to open the dies in terms of the complete martensitic transformation.

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