High Temperature Fatigue Tests of a Cu-Be Alloy and Synthesis in Terms of Linear Elastic Strain Energy Density

2014 ◽  
Vol 627 ◽  
pp. 77-80 ◽  
Author(s):  
F. Berto ◽  
P. Gallo ◽  
P. Lazzarin
Keyword(s):  
High Temperature ◽  
Energy Density ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Control Volume ◽  
Elastic Strain Energy ◽  
Fatigue Tests ◽  
Tension Stress ◽  
High Temperature Fatigue ◽  
Fatigue Data

The present paper summarises the results from uniaxial-tension stress-controlled fatigue tests performed at different temperatures up to 650°C on Cu-Be specimens. Two geometries are considered: hourglass shaped and plates weakened by a central hole (Cu-Be alloy). The motivation of the present work is that, at the best of authors’ knowledge, only a limited number of papers on these alloys under high-temperature fatigue are available in the literature and no results deal with notched components.The Cu-Be specimens fatigue data are re-analyzed in terms of the mean value of the Strain Energy Density (SED) averaged over a control volume. Thanks to the SED approach it is possible to summarise in a single scatter-band all the fatigue data, independently of the specimen geometry.

scholarly journals A New 3D Creep-Fatigue-Elasticity Damage Interaction Diagram Based on the Total Tensile Strain Energy Density Model

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 274 ◽  
Author(s):  
Qiang Wang ◽  
Naiqiang Zhang ◽  
Xishu Wang
Keyword(s):  
High Temperature ◽  
Energy Density ◽  
Fatigue Damage ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Life Prediction ◽  
Tensile Strain ◽  
Elastic Strain Energy ◽  
Interaction Diagram ◽  
Creep Fatigue

Fatigue damage, creep damage, and their interactions are the critical factors in degrading the integrity of most high-temperature engineering structures. A reliable creep-fatigue damage interaction diagram is a crucial issue for the design and assessment of high-temperature components used in power plants. In this paper, a new three-dimensional creep-fatigue-elasticity damage interaction diagram was constructed based on a developed life prediction model for both high-temperature fatigue and creep fatigue. The total tensile strain energy density concept is adopted as a damage parameter for life prediction by using the elastic strain energy density and mean stress concepts. The model was validated by a great deal of data such as P91 steel at 550 °C, Haynes 230 at 850 °C, Alloy 617 at 850 and 950 °C, and Inconel 625 at 815 °C. The estimation values have very high accuracy since nearly all the test data fell into the scatter band of 2.0.

Fatigue Strength of Three Dimensional Welded Joints: A Synthesis Based on the Strain Energy Density over a Control Volume

2007 ◽  
Vol 348-349 ◽  
pp. 413-416
Author(s):  
M. Zappalorto ◽  
Filippo Berto ◽  
Paolo Lazzarin
Keyword(s):  
Experimental Data ◽  
Energy Density ◽  
Welded Joints ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Complex Geometry ◽  
Control Volume ◽  
Three Dimensional ◽  
Weld Toe ◽  
Weld Root

A recent approach based on the local strain energy density (SED) averaged over a given control volume is applied to well documented experimental data taken from the literature, all related to steel welded joints of complex geometry. This small size volume embraces the weld root or the weld toe, both regions modelled as sharp (zero notch radius) V-notches with different opening angles. The SED is evaluated from three-dimensional finite element models by using a circular sector with a radius equal to 0.28 mm. The data expressed in terms of the local energy fall in a scatter band recently reported in the literature, based on about 650 experimental data related to fillet welded joints made of structural steel with failures occurring at the weld toe or at the weld root.

Further Study on the Net Shear Strain Energy Density Theory

2013 ◽  
Vol 423-426 ◽  
pp. 1644-1647
Author(s):  
Shou Yi Xue
Keyword(s):  
Energy Density ◽  
Shear Strain ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
Volumetric Strain ◽  
Material Strength ◽  
Strength Theory ◽  
Shear Strain Energy ◽  
Strain Energy Density Theory

The net shear strain energy density strength theory was systematically explained. Firstly, the composition of elastic strain energy and the roles of their own were analyzed, and it is pointed out that the distortion strain energy is the energy driving failure and the volumetric strain energy can help improve the material strength. Therefore, ultimate energy driving material damage should be the shear strain energy after deducting the friction effect, namely the net shear strain energy, which indicates rationality of the assumption adopted by the net shear strain energy strength theory. Secondly, the empirical laws of geomaterial strength were summarized and explained by using the net shear strain energy theory, which verifies the new theory is appropriate.

scholarly journals A Modified Bursting Energy Index for Evaluating Coal Burst Proneness and Its Application in Ordos Coalfield, China

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1729
Author(s):  
Xuewei Liu ◽  
Quansheng Liu ◽  
Bin Liu ◽  
Yongshui Kang
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Elastic Strain ◽  
Strain Energy ◽  
Coal Mines ◽  
Elastic Strain Energy ◽  
Peak Strength ◽  
Energy Index ◽  
Total Input ◽  
Elastic Strain Energy Density

Coal burst is a type of dynamic geological hazard in coal mine. In this study, a modified bursting energy index, which is defined as the ratio of elastic strain energy at the peak strength to the released strain energy density at the post-peak stage, was proposed to evaluate the coal burst proneness. The calculation method for this index was also introduced. Two coal mines (PJ and TJH coal mines) located in Ordos coalfield were used to verify the validity of the proposed method. The tests results indicate that modified bursting energy index increases linearly with increasing uniaxial compressive strength. The parameter A, which is used to fit relation between total input and elastic strain energy density, has a significant effect on the modified bursting energy index. A large value of parameter A means more elastic strain energy before the peak strength while a small value indicates most of input energy was dissipated. Finally, the coal burst proneness of these two coal mines was evaluated with the modified index. The results of modified index are consistent with that of laboratory tests, and more reasonable than that from original bursting energy index because it removed the dissipated strain energy from the total input strain energy density.

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