scholarly journals Strain response and energy dissipation of floating saline ice under cyclic compressive stress

2020 ◽  
Author(s):  
Mingdong Wei ◽  
Arttu Polojärvi ◽  
David M. Cole ◽  
Malith Prasanna
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Temperature Gradient ◽  
Sea Ice ◽  
Compressive Loading ◽  
Cyclic Stress ◽  
Naturally Occurring ◽  
Physically Based ◽  
Constitutive Response ◽  
Significant Temperature

Abstract. Understanding the mechanical behavior of sea ice is the basis of ice mechanics applications. Laboratory-scale work on saline ice has often involved dry, isothermal ice specimens due to the relative ease of testing. This approach does not address the fact that the natural sea ice is practically always floating in seawater and typically has a significant temperature gradient. To address this important issue, we have developed equipment and methods for conducting compressive loading experiments on floating laboratory-prepared saline ice specimens. The present effort describes these developments and presents the results of stress-controlled cyclic compression experiments. We conducted the experiments on dry, isothermal (−10 °C) ice specimens and on floating ice specimens with a naturally occurring temperature gradient. The experiments involved ice salinities of 5 and 7 ppt, cyclic stress levels ranging from 0.04–0.12 MPa to 0.08–0.25 MPa and cyclic loading frequencies of 10−3 Hz to 1 Hz. The constitutive response and energy dissipation under cyclic loading were successfully analyzed using an existing physically based constitutive model for sea ice. The results highlight the importance of testing warm and floating ice specimens and demonstrate that the experimental method proposed in this study provides a convenient and practical approach to perform laboratory experiments on floating ice.

scholarly journals Strain response and energy dissipation of floating saline ice under cyclic compressive stress

2020 ◽  
Vol 14 (9) ◽  
pp. 2849-2867
Author(s):  
Mingdong Wei ◽  
Arttu Polojärvi ◽  
David M. Cole ◽  
Malith Prasanna
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Temperature Gradient ◽  
Sea Ice ◽  
Compressive Loading ◽  
Cyclic Stress ◽  
Naturally Occurring ◽  
Physically Based ◽  
Constitutive Response ◽  
Significant Temperature

Abstract. Understanding the mechanical behavior of sea ice is the basis of applications of ice mechanics. Laboratory-scale work on saline ice has often involved dry, isothermal ice specimens due to the relative ease of testing. This approach does not address the fact that the natural sea ice is practically always floating in seawater and typically has a significant temperature gradient. To address this important issue, we have developed equipment and methods for conducting compressive loading experiments on floating laboratory-prepared saline ice specimens. The present effort describes these developments and presents the results of stress-controlled sinusoidal cyclic compression experiments. We conducted the experiments on dry, isothermal (−10 ∘C) ice specimens and on floating-ice specimens with a naturally occurring temperature gradient. The experiments involved ice salinities of 5 and 7 ppt, cyclic stress levels ranging from 0.04–0.12 to 0.08–0.25 MPa and cyclic loading frequencies of 0.001 to 1 Hz. The constitutive response and energy dissipation under cyclic loading were successfully analyzed using an existing physically based constitutive model for sea ice. The results highlight the importance of testing warm and floating-ice specimens and demonstrate that the experimental method proposed in this study provides a convenient and practical approach to perform laboratory experiments on floating ice.

Comparing the Seismic Performance of Beam-Column Joints with and without SFRC when Subjected to Cyclic Loading

2012 ◽  
Vol 626 ◽  
pp. 85-89 ◽  
Author(s):  
Kay Dora Abdul Ghani ◽  
Nor Hayati Hamid
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Seismic Performance ◽  
Experimental Work ◽  
Concrete Beam ◽  
Steel Fiber ◽  
Precast Concrete ◽  
Experimental Results ◽  
Column Joint ◽  
Initial Cracks

The experimental work on two full-scale precast concrete beam-column corner joints with corbels was carried out and their seismic performance was examined. The first specimen was constructed without steel fiber, while second specimen was constructed by mixed up steel fiber with concrete and placed it at the corbels area. The specimen were tested under reversible lateral cyclic loading up to ±1.5% drift. The experimental results showed that for the first specimen, the cracks start to occur at +0.5% drifts with spalling of concrete and major cracks were observed at corbel while for the second specimen, the initial cracks were observed at +0.75% with no damage at corbel. In this study, it can be concluded that precast beam-column joint without steel fiber has better ductility and stiffness than precast beam-column joint with steel fiber. However, precast beam-column joint with steel fiber has better energy dissipation and fewer cracks at corbel as compared to precast beam-column joint without steel fiber.

scholarly journals Effect of temperature gradient on heavy quark anti-quark potential using gravity dual model

2020 ◽  
Author(s):  
S Ganesh ◽  
M Mishra
Keyword(s):  
Temperature Gradient ◽  
Gluon Plasma ◽  
Effect Of Temperature ◽  
Dual Model ◽  
Thermal Gradients ◽  
Imaginary Time ◽  
Thermal Systems ◽  
Naturally Occurring ◽  
Quark Potential ◽  
Stationary Approximation

Abstract Thermal systems have traditionally been modeled via Euclideanized space by analytical continuation of time to an imaginary time. We extend the concept to static thermal gradients by recasting the temperature variation as a variation in the Euclidean metric. We apply this prescription to determine the Quark anti-Quark potential in a system with thermal gradient. A naturally occurring QCD medium with thermal gradients is a Quark Gluon Plasma (QGP). However, the QGP evolves in time. Hence, we use a quasi-stationary approximation, which is applicable only if the rate of time evolution is slow. Hence the application of our proposal to a Quark anti-Quark potential in QGP can be seen as a step towards a more exact theory which would incorporate time varying thermal gradients. The effect of a static temperature gradient on the Quark anti-Quark potential is analyzed using a gravity dual model. A non-uniform black string metric is developed, by perturbing the Schwarzchild metric, which allows to incorporate the temperature gradient in the dual AdS space. Finally, an expression for the Quark anti-Quark potential, in the presence of a static temperature gradient, is derived.

scholarly journals Influence of the microstructure on the cyclic stress-strain behaviour and fatigue life in hypo-eutectic Al-Si-Mg cast alloys

2018 ◽  
Vol 165 ◽  
pp. 15004 ◽  
Author(s):  
Jochen Tenkamp ◽  
Alexander Koch ◽  
Stephan Knorre ◽  
Ulrich Krupp ◽  
Wilhelm Michels ◽  
...  
Keyword(s):  
Solid Solution ◽  
Fatigue Life ◽  
Cyclic Loading ◽  
Weight Ratio ◽  
Cyclic Stress ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Eutectic Morphology ◽  
Cast Alloys ◽  
Incremental Step

Aluminium alloys are promising candidates for energy-and cost-efficient components in automotive and aerospace industries, due to their excellent strength-to-weight ratio and relatively low cost compared to titanium alloys. As modern cast processing and post-processing, e.g. hot isostatic pressing, result in decreased frequency and size of defects, the weakest link depends on microstructural characteristics, e.g. secondary dendrite arm spacing (SDAS), Si eutectic morphology and α-Al solid solution hardness. Hereby, fatigue investigations of the effect of the microstructure characteristics on the cyclic stress-strain behaviour as well as fatigue mechanisms in the low cycle and high cycle fatigue regime are performed. For this purpose, samples of the aluminium cast alloy EN AC-AlSi7Mg0.3 with different Si eutectic morphology and α-Al solid solution hardness were investigated. To compare the monotonic and cyclic stress-strain curves, quasistatic tensile tests and incremental step tests were performed on two microstructure conditions. The results show that the cyclic loading leads to a hardening of the material compared to monotonic loading. Based on damage parameter Woehler curves, it is possible to predict the damage progression and fatigue life for monotonic and cyclic loading in hypo-eutectic Al-Si-Mg cast alloys by one power law.

scholarly journals Results from the implementation of the elastic viscous plastic sea ice rheology in HadCM3

2006 ◽  
Vol 3 (4) ◽  
pp. 777-803
Author(s):  
W. Connolley ◽  
A. Keen ◽  
A. McLaren
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Climate Model ◽  
Ice Dynamics ◽  
Sea Ice Dynamics ◽  
Future Improvement ◽  
Physically Based ◽  
Solid Foundation ◽  
Hadley Centre ◽  
Better Than

Abstract. We present results of an implementation of the Elastic Viscous Plastic (EVP) sea ice dynamics scheme into the Hadley Centre coupled ocean-atmosphere climate model HadCM3. Although the large-scale simulation of sea ice in HadCM3 is quite good with this model, the lack of a full dynamical model leads to errors in the detailed representation of sea ice and limits our confidence in its future predictions. We find that introducing the EVP scheme results in a worse initial simulation of the sea ice. This paper documents various improvements made to improve the simulation, resulting in a sea ice simulation that is better than the original HadCM3 scheme overall. Importantly, it is more physically based and provides a more solid foundation for future improvement. We then consider the interannual variability of the sea ice in the new model and demonstrate improvements over the HadCM3 simulation.

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