Ice Force Prediction Using a Limited Driving Force Approach

1981 ◽  
Author(s):  
Vitoon Vivatrat ◽  
John R. Krelder
Keyword(s):  
Driving Force ◽  
Force Prediction ◽  
Ice Force

Ice Force Prediction Using a Limited Driving Force Approach

1983 ◽  
Vol 105 (1) ◽  
pp. 17-25 ◽  
Author(s):  
J. R. Kreider ◽  
V. Vivatrat
Keyword(s):  
Driving Force ◽  
Driving Forces ◽  
Offshore Structures ◽  
First Year ◽  
Local Concentration ◽  
Order Of Magnitude ◽  
Failure Loads ◽  
Ice Loads ◽  
Ice Field ◽  
Ice Force

This paper discusses the importance of environmental driving forces in determining ice loads on Arctic offshore structures. Limits to the environmental driving force in a first-year ice field are analyzed by considering models of ridge formation, wind and current driving forces, and irregularities such as leads and tidal cracks. Average driving forces are estimated to be approximately 10–50 kips/ft for far-field, with some local concentration near fixed structures. These order of magnitude estimates are sufficiently less than failure loads for many ice features to indicate that limited driving force approach may reduce estimated ice loads on Arctic structures.

scholarly journals Soil Parameter Identification and Driving Force Prediction for Wheel-Terrain Interaction

10.5772/6225 ◽  
2008 ◽  
Vol 5 (4) ◽  
pp. 35 ◽  
Author(s):  
Suksun Hutangkabodee ◽  
Yahya Zweiri ◽  
Lakmal Seneviratne ◽  
Kaspar Althoefer
Keyword(s):  
Driving Force ◽  
Driving Forces ◽  
Interaction Model ◽  
Soil Parameters ◽  
Wheel Slip ◽  
Force Prediction ◽  
High Inflation ◽  
Generalized Newton ◽  
Drawbar Pull ◽  
Wheeled Vehicles

This paper considers wheeled vehicles traversing unknown terrain, and proposes an approach for identifying the unknown soil parameters required for vehicle driving force prediction (drawbar pull prediction). The predicted drawbar pull can potentially be employed for traversability prediction, traction control, and trajectory following which, in turn, improve overall performance of off-road wheeled vehicles. The proposed algorithm uses an approximated form of the wheel-terrain interaction model and the Generalized Newton Raphson method to identify terrain parameters in real-time. With few measurements of wheel slip, i, vehicle sinkage, z, and drawbar pull, DP, samples, the algorithm is capable of identifying all the soil parameters required to predict vehicle driving forces over an entire range of wheel slip. The algorithm is validated with experimental data from a wheel-terrain interaction test rig. The identified soil parameters are used to predict the drawbar pull with good accuracy. The technique presented in this paper can be applied to any vehicle with rigid wheels or deformable wheels with relatively high inflation pressure, to predict driving forces in unknown environments.

Crack driving force prediction in heterogeneous welds using Vickers hardness maps and hardness transfer functions

2018 ◽  
Vol 201 ◽  
pp. 322-335 ◽  
Author(s):  
Sameera Naib ◽  
Wim De Waele ◽  
Primož Štefane ◽  
Nenad Gubeljak ◽  
Stijn Hertelé
Keyword(s):  
Vickers Hardness ◽  
Driving Force ◽  
Transfer Functions ◽  
Crack Driving Force ◽  
Force Prediction

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

The nucleation of cavities at grain boundaries

1987 ◽  
Vol 45 ◽  
pp. 288-291
Author(s):  
P. J. Goodhew
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Grain Boundaries ◽  
Radiation Damage ◽  
Impurity Concentration ◽  
Driving Force ◽  
Nucleation And Growth ◽  
Phase Boundaries ◽  
Cavity Nucleation ◽  
Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

Sign in / Sign up

Export Citation Format

Share Document