scholarly journals Stabilisation with geogrids for transport applications – selected issues

2019 ◽  
Vol 265 ◽  
pp. 01001 ◽  
Author(s):  
Jacek Kawalec
Keyword(s):  
Mechanical Properties ◽  
Granular Material ◽  
Soil Particle ◽  
Particle Movement ◽  
Long Time ◽  
Unbound Granular Material

Stabilisation is defined as improvement of the mechanical properties of an unbound granular material by including one or more geosynthetic layers such that the deformation under applied loads is reduced by minimizing soil particle movement. Paper discuss geogrids as type of geosynthetics which when used in stabilisation function for transport applications could provide real improvement in performance of aggregate layer. Such function has been called for a quite long time as the reinforcement of subbase, base or ballast, depending on the application

Stress fields in granular material and implications for performance of robot locomotion over granular media

2015 ◽  
Vol 8 (1) ◽  
pp. 2005-2009
Author(s):  
Diandong Ren ◽  
Lance M. Leslie ◽  
Congbin Fu
Keyword(s):  
Mechanical Properties ◽  
Granular Material ◽  
Granular Media ◽  
Rotation Frequency ◽  
Legged Locomotion ◽  
Working Environment ◽  
Navier Stokes ◽  
Maximum Speed ◽  
Sigmoid Curve ◽  
Multi Body

 Legged locomotion of robots has advantages in reducing payload in contexts such as travel over deserts or in planet surfaces. A recent study (Li et al. 2013) partially addresses this issue by examining legged locomotion over granular media (GM). However, they miss one extremely significant fact. When the robot’s wheels (legs) run over GM, the granules are set into motion. Hence, unlike the study of Li et al. (2013), the viscosity of the GM must be included to simulate the kinematic energy loss in striking and passing through the GM. Here the locomotion in their experiments is re-examined using an advanced Navier-Stokes framework with a parameterized granular viscosity. It is found that the performance efficiency of a robot, measured by the maximum speed attainable, follows a six-parameter sigmoid curve when plotted against rotating frequency. A correct scaling for the turning point of the sigmoid curve involves the footprint size, rotation frequency and weight of the robot. Our proposed granular response to a load, or the ‘influencing domain’ concept points out that there is no hydrostatic balance within granular material. The balance is a synergic action of multi-body solids. A solid (of whatever density) may stay in equilibrium at an arbitrary depth inside the GM. It is shown that there exists only a minimum set-in depth and there is no maximum or optimal depth. The set-in depth of a moving robot is a combination of its weight, footprint, thrusting/stroking frequency, surface property of the legs against GM with which it has direct contact, and internal mechanical properties of the GM. If the vehicle’s working environment is known, the wheel-granular interaction and the granular mechanical properties can be grouped together. The unitless combination of the other three can form invariants to scale the performance of various designs of wheels/legs. Wider wheel/leg widths increase the maximum achievable speed if all other parameters are unchanged.

Development of a New Mechanistic Empirical Rutting Model for Unbound Granular Material

2016 ◽  
Vol 28 (8) ◽  
pp. 04016051 ◽  
Author(s):  
Fan Gu ◽  
Yuqing Zhang ◽  
Charles V. Droddy ◽  
Rong Luo ◽  
Robert L. Lytton
Keyword(s):  
Granular Material ◽  
Unbound Granular Material

scholarly journals PENGARUH SPUTTERING TiN TERHADAP KEKASARAN, KEKERASAN PERMUKAAN MATERIAL AISI316L

2019 ◽  
Vol 18 (3) ◽  
pp. 331-338
Author(s):  
Jemssy Ronald Rohi ◽  
Priyo Tri Iswanto ◽  
Tjipto Sujitno ◽  
Erich Umbu Kondi
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Corrosion Resistance ◽  
Deposition Time ◽  
Low Cost ◽  
Surface Hardness ◽  
The Body ◽  
Aisi 316L ◽  
Good Corrosion Resistance ◽  
Long Time

AISI 316L is widely used for implantation in orthopedic surgery due to its good corrosion resistance, mechanical properties and low cost. However, AISI 316L is not well suited for biocompatibility with the body, so implant material with AISI 316L can’t be used for a long time. One way to improve the corrosion resistance and mechanical properties of AISI 316L is to perform a surface treatment such as sputtering. This study discusses the effect of deposition sputtering TiN of 60, 90, 120 and 150 minutes on roughness and surface hardness at a ratio of argon gas and nitrogen to 80% Ar:20% N2. The results of the surface roughness value of the TiN sputtering layer deposited to AISI 316L for 60, 90, 120, and 150 minutes were 0.02 μm, 0.04 μm, 0.06 μm, and 0.04 μm respectively. This shows that the coating time of TiN in AISI 316L has no significant influence on value of surface roughness. Surface hardness results at 60, 90, 120, and 150 minutes were obtained with 268 HVN, 275 HVN, 278 HVN and 282 HVN. Increased hardness value, as the TiN thin layer has a higher hardness value compared to AISI 316L. The longer the deposition time, the more layers are formed and the layer becomes thicker. With the thickness of the layer, the density at the grain boundary increases. Because the higher density leads to grain growth, in which form micropores.

scholarly journals Diffusion Bonding of Ti6Al4V at Low Temperature via SMAT

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 94
Author(s):  
Yuqing Chen ◽  
Guofeng Wang ◽  
Yongkang Liu ◽  
Liqiang Zhan ◽  
He Diao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Diffusion Bonding ◽  
Welded Joint ◽  
Surface Mechanical Attrition Treatment ◽  
Mechanical Attrition ◽  
Long Time ◽  
Tc4 Alloy ◽  
Heat Preservation ◽  
Maximum Shear Strength

Titanium alloys used to be welded to gain good joint strength at 920 °C through diffusion bonding. However, due to the heat preservation at high temperatures for a long time, we obtain joints with great bond strength while the mechanical properties of the sheet are lost. In this paper, taking Ti6Al4V alloy as an example, we studied the microstructure of the surface under the different times of surface mechanical attrition treatment (SMAT). In addition, the microstructure and mechanical properties after diffusion bonding at 800 °C-5 MPa-1 h were also conducted. The results show that the shear strength of TC4 alloy welded joint after SMAT treatment is improved, and the maximum shear strength can reach 797.7 MPa, up about 32.4%

scholarly journals Ut vis sic tensio

2018 ◽  
Vol 45 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Giuseppe Saccomandi
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Elastic Strain ◽  
Strain Energy ◽  
Nonlinear Response ◽  
Solid Mechanics ◽  
Functional Form ◽  
Elastic Strain Energy ◽  
Strongly Nonlinear ◽  
Long Time

The mechanical properties of rubber-like materials have been offering an outstanding challenge to the solid mechanics community for a long time. The behaviour of such materials is quite difficult to predict because rubber self-organizes into mesoscopic physical structures that play a prominent role in determining their complex, history-dependent and strongly nonlinear response. In this framework one of the main problems is to find a functional form of the elastic strain-energy that best describes the experimental data in a mathematical feasible way. The aim of this paper is to give a survey of recent advances aimed at solving such a problem.

Influence of Storage Conditions on Quality of Fly Ashes

2014 ◽  
Vol 1000 ◽  
pp. 59-62
Author(s):  
Hana Kalousová ◽  
Eva Bartoníčková ◽  
Tomáš Opravil
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Storage Conditions ◽  
Fly Ashes ◽  
Volume Stability ◽  
Stock Pile ◽  
Long Time ◽  
Made In

The presented paper deals with the issue of influence of storage conditions on the quality of conventional fly ashes which are produced by combustion of lignite. These ashes were stockpiled for long time. A borehole for sampling was made in the fly ash stock-pile. Total depth of the borehole was 20 m. Samples of fly ashes taken from every single meter were analyzed and next mechanical properties and the volume stability of materials containing these fly ashes were tested. The quality of fly ashes especially with respect to the possibility to use them as components of pastes, mortars and concretes as pozzolanic admixture or fine filler was evaluated.

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