Test Method for Time-Dependent (Creep) Deformation Under Constant Pressure for Geosynthetic Drainage Products

The equivalence of magnetic field line equations to a one-dimensional time-dependent Hamiltonian system is used to construct magnetic fields with arbitrary toroidal magnetic surfaces I = const. For this purpose Hamiltonians H which together with their invariants satisfy periodicity constraints have to be known. The choice of H fixes the rotational transform η(I). Arbitrary axisymmetric fields, and nonaxisymmetric fields with constant η(I) are considered in detail.Configurations with coinciding magnetic and current density surfaces are obtained. The approach used is not well suited, however, to satisfying the additional MHD equilibrium condition of constant pressure on magnetic surfaces.

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Evaluation of Creep Deformation Property of Grade 91 Steels

Volume 6B: Materials and Fabrication ◽

10.1115/pvp2015-45405 ◽

2015 ◽

Cited By ~ 1

Author(s):

Kazuhiro Kimura ◽

Kota Sawada ◽

Hideaki Kushima

Keyword(s):

Creep Rate ◽

Creep Deformation ◽

Minimum Creep Rate ◽

Deformation Property ◽

Time Dependent ◽

Tertiary Creep ◽

Total Strain ◽

Dominant Factor ◽

Creep Equation ◽

Time To Rupture

Creep deformation property of Grade T91 steels over a range of temperatures from 550 to 625°C was analyzed by means of the empirical creep equation reported in the previous study [1]. The creep equation consists of four time dependent terms and one constant and time to rupture is estimated as a time to total strain of 10%. Accuracy of the creep equation to represent creep curve and to predict time to rupture and minimum creep rate was indicated. Times to minimum creep rate, total strain of 1%, initiation of tertiary creep and rupture were evaluated by the creep equation. Stress dependence of strains at minimum creep rate and the initiation of tertiary creep were analyzed. Contribution of four time dependent terms to the strains at minimum creep rate, total strain of 1% and initiation of tertiary creep was investigated. Three parameters to determine a temperature and time-dependent stress intensity limit, St, were compared and a dominant factor of St was examined. Heat-to-heat variation of the creep deformation property was investigated on two heats of T91 steels contain low and high nickel concentrations.

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Modeling of Stiffness Reduction of Vibration Conveyor Springs Subjected to Ultra High Cyclic Loading under High Humidity

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.471-472.975 ◽

2011 ◽

Vol 471-472 ◽

pp. 975-980

Author(s):

Takahiko Yoshi ◽

Kazuya Okubo ◽

Toru Fujii

Keyword(s):

Crack Propagation ◽

Creep Deformation ◽

Crack Tip ◽

Time Dependent ◽

High Humidity ◽

Humidity Condition ◽

Stiffness Reduction ◽

Carbon Fiber Cloth ◽

Plate Spring ◽

High Humidity Condition

Significant stiffness reduction of the plate spring due to delaminations around the interwoven cloths could be prevented by using CFRTP (carbon fiber cloth and Polyethylene Terephthalate (PET)) rather than that by using CFRP (carbon fiber cloth and epoxy), when ultra high cyclic loading was applied to the plate spring under high humidity condition. To explain the result, the prediction model of stiffness reduction was introduced considering time-dependent crack propagation accompanying with creep deformation around the crack tip. Stiffness reduction of CFRP under high humidity condition was not only determined by cyclic crack propagation but also by time-dependent crack propagation accompanying with creep deformation around the crack tip. It was found that CFRTP was effective material of the plate springs on vibration conveyer for the uses under high humidity condition to prevent significant stiffness reduction, where the crack propagation accompanying with creep deformation should be prevented around the crack tip.

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Magnesium nanocomposites: An overview on time-dependent plastic (creep) deformation

Defence Technology ◽

10.1016/j.dt.2018.08.008 ◽

2019 ◽

Vol 15 (2) ◽

pp. 123-131 ◽

Cited By ~ 7

Author(s):

M. Haghshenas ◽

M. Gupta

Keyword(s):

Creep Deformation ◽

Time Dependent ◽

Plastic Creep

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Time-Dependent Laminar Flow in Curved Channels

Journal of Applied Mechanics ◽

10.1115/1.3408617 ◽

1970 ◽

Vol 37 (3) ◽

pp. 838-843 ◽

Cited By ~ 1

Author(s):

R. J. Nunge

Keyword(s):

Laminar Flow ◽

Pressure Gradient ◽

Constant Pressure ◽

Time Dependent ◽

Pressure Gradients ◽

Straight Channel ◽

Curvature Ratio ◽

Curved Channels ◽

Developing Flow ◽

Time Required

The velocity distribution for time-dependent laminar flow in curved channels is derived. The analysis applies to flows with pressure gradients which are arbitrary functions of time. Numerical results are obtained for developing flow due to a constant pressure gradient. Developing flow in a straight channel is also discussed and it is found that the curvature ratio has only a small effect on the time required to reach the fully developed state.

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