نتایج جستجو برای: mission creep

تعداد نتایج: 44916  

2014
Hidenari Takagi Ming Dao Masami Fujiwara

Indentation creep tests and finite element simulations were performed on a model material to show that the constitutive equation for conventional uniaxial creep can be derived using the instrumented indentation testing technique. When the indentation pressure and the indentation creep rate are maintained at constant values of ps and _ 3⁄4inðsÞ, respectively, the contours of the equivalent stres...

2017
Dan Liu Dirk John Pons

Background—Creep-fatigue behavior is identified as the incorporated effects of fatigue and creep. One class of constitutive-based models attempts to evaluate creep and fatigue separately, but the interaction of fatigue and creep is neglected. Other models treat the damage as a single component, but the complex numerical structures that result are inconvenient for engineering application. The mo...

2014
William Harrison Zakaria Abdallah Mark Whittaker

Gamma titanium aluminides (γ-TiAl) display significantly improved high temperature mechanical properties over conventional titanium alloys. Due to their low densities, these alloys are increasingly becoming strong candidates to replace nickel-base superalloys in future gas turbine aeroengine components. To determine the safe operating life of such components, a good understanding of their creep...

1976
J. N. Webb

SUMMARY c The concept that creep response is the result of a transient approach to a minimum strain rate continuously modified by accumulating damage has been investigated using high precision creep data. It was considered that the accumulated creep strain might be some measure of internal damage and curves of log creep strain rate against creep strain are shown to exhibit linearity at higher s...

2012
Holger Keitel

The prediction of long-term deformations of concrete and reinforced concrete structures has been a field of extensive research and several different creep models have been developed so far. Most of the models were developed for constant concrete stresses, thus, in case of varying stresses a specific superposition principle or time-integration, respectively, is necessary. Nowadays, when modeling...

2010
JOHN W. GLEN DAVID J. IVES

Creep polycrystalline ice samples antifreeze glycopeptides re-accelerating or tertiary samples. Previous work grain-boundary migration consistent with this, as nucleation and growth of curves containing (AFGPs) creep that has shown obtained from the low concentrations of do not show the is found in pure ice that AFGPs inhibit in ice and the present results are tertiary creep is associated with ...

2004
Y. H. PARK J. W. HOLMES

The tensile creep and creep-recovery behaviour of a unidirectional SiC fibre-Si3N4 matrix composite was analysed using finite element techniques. The analysis, based on the elastic and creep properties of each constituent, considered the influence of fibre-matrix bonding and processing-related residual stresses on creep and creep-recovery behaviour. Both twoand threedimensional finite element m...

2009
Qinglin Wu Jong N. Lee Zhiyong Cai Dingguo Zhou

Creep performance of zinc borate-treated strandboard from southern pine (Pinus taeda L.) and red oak (Quercus falcata) was investigated at 25°C temperature and 65% relative humidity. It was shown that the borate treatment had some signifi cant effect on creep defl ection of the test panels, and the effect varied with wood species. There was no signifi cant effect of creep loading on residual be...

2017
James Coakley Dong Ma Matthew Frost David Dye David N. Seidman David C. Dunand Howard J. Stone

In-situ neutron diffraction measurements were performed on monocrystalline samples of the Ni-based superalloy CMSX-4 during N-type g0 raft formation under the tensile creep conditions of 1150 C/ 100 MPa, and subsequently on a rafted sample under the low temperature/high stress creep conditions of 715 C/825 MPa. During 1150 C/100 MPa creep, the g0 volume fraction decreased from ~70% to ~50%, the...

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