A new prediction method of fatigue-creep interaction behavior based on total strain energy for high strength super alloy.

A law on the cumulative damage is presented basing on total strain energy induced as damage parameter to calculate the cumulative damage when the specimens of concrete subjected to fatigue loading.Then the maximum of critical cumulative damage and location of production are determined basing on the equation of cumulative fatigue damage combined with experimental result through using the finite element analysis and the critical plane method in fatigue analysis.The relation equation between the standardized critical total strain energy density and stress level is obtained by considering the impact of loading level.The fatigue life of specimens can be predicted by combining the equation of cumulative fatigue damage with the relation equation of damage and stress level and the prediction results coincide with experimental results very well.

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Effects of Lateral Limited Area and Substrate Compliance on Strain Distribution and Critical Thickness of Sige Film on Si Mesa Substrates

MRS Proceedings ◽

10.1557/proc-379-61 ◽

1995 ◽

Vol 379 ◽

Author(s):

Zhang Rong ◽

Huang Hongbin ◽

Shi Yi ◽

Yang Kai ◽

Gu Shulin ◽

...

Keyword(s):

Strain Distribution ◽

Strain Energy ◽

Critical Thickness ◽

Total Strain ◽

Limited Area ◽

Lateral Size ◽

Total Strain Energy

ABSTRACTIn this paper, we calculated theoretically the strain distribution and the critical thickness of the SiGe epilayers on Si(100) mesa structural substrates by considering the effect of the compliance of substrates, along with the effect of the limited area, and found that the compliance of substrates was relevant not only to its thickness, but also to their lateral size. The introduction of substrate compliance significantly reduced the total strain energy in the epilayers, and increased the critical thickness. That approach was realized by growth on the mesa substrates. The TEM observations confirmed the results of calculations.

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The Effect of Compressive Damage on Tensile Loading Failure of Titanium 6Al-4V

Volume 7: Structures and Dynamics, Parts A and B ◽

10.1115/gt2012-69079 ◽

2012 ◽

Author(s):

Onome Scott-Emuakpor ◽

Tommy George ◽

John Wertz ◽

Casey Holycross

Keyword(s):

Strain Energy ◽

Tensile Loading ◽

Damage Parameter ◽

Total Strain ◽

Tensile Fracture ◽

Half Cycle ◽

Physical Damage ◽

Total Strain Energy ◽

Tension And Compression ◽

Compressive Damage

In order to explore the belief that total strain energy accumulation during monotonic tensile fracture is a universal damage parameter, the effect of compressive preloads on specimens failed via tensile loading is analyzed. The motivation behind this analysis is due to the theory of an energy-based life prediction model, which states that the total strain energy required for monotonic tensile fracture is defined as the physical damage quantity for the fatigue lifing model. Two things are observed in order to determine the effects of a compressive preload on tensile monotonic fracture. First, the compressive work is viewed as accumulated damage, thus adding to the total work necessary for failure. Second, tensile works of fractured specimens with and without stored compressive energy are compared to see if the damage parameter is affected. The analysis is conducted through experimental data acquisition from round stock Titanium 6Al-4V dogbone specimens. The results from this study show that compressive damage has a negligible effect on monotonic tensile work to fracture, and combined half-cycle tension and compression preloads have an unnoticeable effect on the tensile work of the final pull to fracture. These results contradict the theory and research validations of the energy-based predictions; however, they provide a platform for future efforts to understand the strain energy correlation between monotonic, low cycle and high cycle failures.

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Analysis of Multi-Stable Architectures for Morphing Structures

ASME 2020 Conference on Smart Materials, Adaptive Structures and Intelligent Systems ◽

10.1115/smasis2020-2395 ◽

2020 ◽

Author(s):

Anil Erol ◽

Jeffery Baur

Keyword(s):

Energy Density ◽

Strain Energy Density ◽

Strain Energy ◽

Compressive Loading ◽

Total Strain ◽

Total Strain Energy ◽

Wide Range ◽

Unit Cells ◽

Mechanical Logic ◽

The Individual

Abstract The field of multi-stable structures has been steadily growing due to a wide range of potential applications including energy harvesting, MEMS, and mechanical logic. This work focuses on utilizing elastic energy trapping and snap-through phenomena of bistable unit cells to design a latticed, hierarchical multi-stable cylinder that can articulate up to 30 degrees from its center axis. The employment of bistable elements is hypothesized to reduce the total strain energy required to articulate the cylinder, and yield faster responses with the snap-through. While multi-stable cylinders exist in previous studies, there have been no previous attempts at studying different modes of deformation beyond compressive loading. Thus, the current work presents a new problem regarding the effects of bistable elements in a latticed cylinder that is carrying tensile, compressive, and shear loadings and exhibiting large displacements as the cylinder is articulated.. The total strain energy density of the articulating cylinder is investigated as a function of the heights of the unit cells, which aids in determining an ideal height for the design that minimizes the strain energy density. Results show that the strain energy of an articulating cylinder can be minimized with the use of multi-stability, and that a multi-stable cylinder can require up to three times less loads to maintain desired articulation compared to a mono-stable structure. These results will lead to future works on further optimizing the articulating cylinder by varying additional parameters like the individual heights of rows, the thicknesses of unit cell beams, the strain energy density, and the initial loading threshold for articulation. In addition, the work in this study can yield methodologies for designing arbitrarily morphing skins beyond just cylindrical geometries.

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Effective properties of composite material based on total strain energy equivalence

Composites Part B Engineering ◽

10.1016/j.compositesb.2018.11.094 ◽

2019 ◽

Vol 166 ◽

pp. 213-220 ◽

Cited By ~ 3

Author(s):

Anna Wiśniewska ◽

Szymon Hernik ◽

Aneta Liber-Kneć ◽

Halina Egner

Keyword(s):

Composite Material ◽

Strain Energy ◽

Effective Properties ◽

Total Strain ◽

Total Strain Energy ◽

Energy Equivalence

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Indices to Determine the Reliability of Rocks under Fatigue Load Based on Strain Energy Method

Applied Sciences ◽

10.3390/app9030360 ◽

2019 ◽

Vol 9 (3) ◽

pp. 360 ◽

Cited By ~ 2

Author(s):

Huanran Fu ◽

Sijing Wang ◽

Xiangjun Pei ◽

Weichang Chen

Keyword(s):

Elastic Modulus ◽

Energy Density ◽

Strain Energy Density ◽

Strain Energy ◽

Total Strain ◽

Fatigue Load ◽

Total Strain Energy ◽

Rock Engineering ◽

Rock Types ◽

Total Strain Energy Density

Rock is a complicated material which includes randomly distributed grains and cracks. The reliability of rocks under fatigue load is very important during the construction and operation of rock engineering. In this paper, we studied the deformation and failure process of red sandstone under fatigue load in a laboratory based on a new division method of strain energy types. The traditional elastic strain energy density is divided into two categories: grain strain energy density and crack strain energy density. We find that the proportion of the grain strain energy density to total strain energy density can be used as an indicator of rock yield and the proportion of the crack strain energy density to total strain energy density can be used as an indicator of rock failure. Subsequently, through extensive literature research, we found that such a phenomenon is widespread. We also find the proportion of grain strain energy density to total strain energy density when yielding is affected by rock types and elastic modulus. The proportion of crack strain energy density to total strain energy density in the pre-peak stage is stable and not affected by rock types and elastic modulus, which is about 0.04~0.13. These findings should be very helpful for rock stable state judging in rock engineering.

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