scholarly journals Crack paths in multiaxial fatigue of C45 steel specimens and correlation of lifetime with the thermal energy dissipation

2021 ◽  
Vol 16 (59) ◽  
pp. 525-536
Author(s):  
Daniele Rigon ◽  
Filippo Berto ◽  
Giovanni Meneghetti
Keyword(s):  
Energy Dissipation ◽  
Thermal Energy ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Load Condition ◽  
Crack Size ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Thermal Energy Dissipation ◽  
Crack Paths

The work deals with the analysis of the multiaxial fatigue damage of a C45 steel and its relationship with the thermal energy dissipation used in the last decades to estimate the uniaxial fatigue behavior of metals. For this purpose, thin-walled samples made of quenched and tempered C45 steel were tested under completely reversed combined axial and torsional cyclic loadings with different biaxiality ratios and phase-shift angles. The analyses of the crack paths at the initiation of the failure were performed after a 50% of stiffness loss that corresponded to a crack size ranging from 10 to 20 mm; afterwards, the characteristic crack paths of each loading condition were analysed by using a digital microscope to identify the direction of the crack at the initiation. The fatigue crack initiation points were inspected using a Scanning Electron Microscope after having broken under static tensile loading all specimens previously tested under fatigue. The specific heat loss per cycle was measured during the fatigue tests by applying the cooling gradient technique. Nevertheless, the fatigue damages observed are dependent on the load condition, the Q parameter was able to collapse all the axial, torsional and multiaxial fatigue test results in a sole scatter band

Thermal-Energy Dissipation

1982 ◽  
Vol 70 (4) ◽  
pp. 475-480 ◽  
Author(s):  
Kenneth H. Cohn ◽  
James W. May
Keyword(s):  
Energy Dissipation ◽  
Thermal Energy ◽  
Thermal Energy Dissipation

Thermal Energy Dissipation by SiO2-Coated Plasmonic-Superparamagnetic Nanoparticles in Alternating Magnetic Fields

2013 ◽  
Vol 25 (22) ◽  
pp. 4603-4612 ◽  
Author(s):  
Georgios A. Sotiriou ◽  
Michelle A. Visbal-Onufrak ◽  
Alexandra Teleki ◽  
Eduardo J. Juan ◽  
Ann M. Hirt ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Magnetic Fields ◽  
Thermal Energy ◽  
Superparamagnetic Nanoparticles ◽  
Thermal Energy Dissipation ◽  
Alternating Magnetic Fields

Effect of Plasma Nitriding on Ultra-High Cycle Fatigue Behaviors of Ti-6Al-4V

2011 ◽  
Vol 295-297 ◽  
pp. 2386-2389 ◽  
Author(s):  
Ren Hui Tian ◽  
Qiao Lin Ouyang ◽  
Qing Yuan Wang
Keyword(s):  
High Cycle Fatigue ◽  
Plasma Nitriding ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Ultra High Cycle Fatigue ◽  
Stress Ratios

In order to investigate the effect of plasma nitriding treatment on fatigue behavior of titanium alloys, very high cycle fatigue tests were carried out for Ti-6Al-4V alloy using an ultrasonic fatigue machine under load control conditions for stress ratios of R=-1 at frequency of ƒ=20KHz. Experiment results showed that plasma nitriding treatment played the principal role in the internal fatigue crack initiation. More importantly, plasma nitriding treatment had a detrimental effect on fatigue properties of the investigated Ti-6Al-4V alloy, and the fatigue strength of material after plasma nitriding treatment appeared to be significantly reduced about 17% over the untreated material.

Wide variation of winter-induced sustained thermal energy dissipation in conifers: a common-garden study

Oecologia ◽  
2021 ◽  
Author(s):  
A. Walter-McNeill ◽  
M. A. Garcia ◽  
B. A. Logan ◽  
D. M. Bombard ◽  
J. S. Reblin ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Thermal Energy ◽  
Common Garden ◽  
Thermal Energy Dissipation

scholarly journals Lhcx proteins provide photoprotection via thermal dissipation of absorbed light in the diatom Phaeodactylum tricornutum

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jochen M. Buck ◽  
Jonathan Sherman ◽  
Carolina Río Bártulos ◽  
Manuel Serif ◽  
Marc Halder ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Cross Section ◽  
Thermal Energy ◽  
Absorption Cross Section ◽  
Phaeodactylum Tricornutum ◽  
Thermal Dissipation ◽  
Absorption Cross ◽  
Dissipation Process ◽  
Thermal Energy Dissipation ◽  
Holistic Understanding

Abstract Diatoms possess an impressive capacity for rapidly inducible thermal dissipation of excess absorbed energy (qE), provided by the xanthophyll diatoxanthin and Lhcx proteins. By knocking out the Lhcx1 and Lhcx2 genes individually in Phaeodactylum tricornutum strain 4 and complementing the knockout lines with different Lhcx proteins, multiple mutants with varying qE capacities are obtained, ranging from zero to high values. We demonstrate that qE is entirely dependent on the concerted action of diatoxanthin and Lhcx proteins, with Lhcx1, Lhcx2 and Lhcx3 having similar functions. Moreover, we establish a clear link between Lhcx1/2/3 mediated inducible thermal energy dissipation and a reduction in the functional absorption cross-section of photosystem II. This regulation of the functional absorption cross-section can be tuned by altered Lhcx protein expression in response to environmental conditions. Our results provide a holistic understanding of the rapidly inducible thermal energy dissipation process and its mechanistic implications in diatoms.

scholarly journals Modeling irreversible molecular internal conversion using the time-dependent variational approach with sD2 ansatz

2020 ◽  
Vol 22 (16) ◽  
pp. 8952-8962
Author(s):  
Mantas Jakučionis ◽  
Tomas Mancal ◽  
Darius Abramavičius
Keyword(s):  
Energy Dissipation ◽  
Thermal Energy ◽  
Variational Approach ◽  
Internal Conversion ◽  
Time Dependent ◽  
Thermal Energy Dissipation

A model of irreversible molecular internal conversion dynamics due to molecular thermal energy dissipation to the bath is presented.

scholarly journals Physiological Characteristics of Photosynthesis in Yellow-Green, Green and Dark-Green Chinese Kale (Brassica oleracea L. var. alboglabra Musil.) under Varying Light Intensities

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 960
Author(s):  
Kuan-Hung Lin ◽  
Feng-Chi Shih ◽  
Meng-Yuan Huang ◽  
Jen-Hsien Weng
Keyword(s):  
Electron Transport ◽  
Energy Dissipation ◽  
Light Intensity ◽  
Thermal Energy ◽  
Electron Transport Rate ◽  
Transport Rate ◽  
Physiological Characteristics ◽  
Chinese Kale ◽  
Thermal Energy Dissipation ◽  
Dark Green

The objective of this work was to study physiological characteristics and photosynthetic apparatus in differentially pigmented leaves of three Chinese kale cultivars. Chlorophyll (Chl) fluorescence and photochemical reflectance index (PRI) measurements in green, yellow-green, and dark-green cultivars in response to varying light intensities. As light intensity increased from 200 to 2000 photosynthetic photon flux density (PPFD), fraction of light absorbed in photosystem (PS) II and PRI values in all plants were strongly lowered, but fraction of light absorbed in PSII dissipated via thermal energy dissipation and non-photochemical quenching (NPQ) values in all plants wereremarkably elevated.When plants were exposed to 200 PPFD, the values of fraction of light absorbed in PSII, utilized in photosynthetic electron transport(p), andfraction of light absorbed excitation energy in PSII dissipated via thermal energy dissipation (D), remained stable regardless of the changes in levels of Chla + b. Under 800 and 1200 PPFD, the values of p and electron transport rate (ETR) decreased, but D and NPQ increased as Chla + bcontent decreased, suggesting that decrease inChla + bcontent led to lower PSII efficiency and it became necessary to increase dissipate excess energy. On the contrary, in 2000 PPFD, leaves with lower Chla + bcontent had relatively higher p and electron transport rate (ETR) values and lower D level, as well as tended to increase more in NPQ but decrease more in PRI values. The consistent relations between PRI and NPQ suggest that NPQ is mainly consisted ofthe xanthophyll cycle-dependentenergy quenching.Yellow-green cultivar showed lower Chla + bcontent but high carotenoids/Chla + b ratio and had high light protection ability under high PPFD. The precise management of photosynthetic parameters in response to light intensity can maximize the growth and development of Chinese kale plants.

scholarly journals Multiaxial fatigue behavior of 2618 aluminum alloy

2019 ◽  
Vol 300 ◽  
pp. 09003
Author(s):  
Benaïssa Malek ◽  
Catherine Mabru ◽  
Michel Chaussumier
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Internal Pressure ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Mean Stress ◽  
Research Project ◽  
Pressure Tests

The purpose of the present research project is to study multiaxial fatigue behavior of 2618 alloy. The influence of mean stress on the fatigue behavior under tension and torsion is particularly investigated. Fatigue tests under combined tensile-torsion, in or out of phase, as well as combined tensile-torsion-internal pressure tests have also been conducted. Multiaxial fatigue results are analyzed according to Fatemi-Socie criterion to predict the fatigue life.

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