Based on the assumption of linear relationship between section deformation, creep and stress and the theory of linear creep, the redistribution of creep stress of concrete structure with different loading ages are discussed. The calculation method and theories of creep stress redistribution are studied, and the computing formulas are developed.
An introduction is given to the classic Weibull statistical theory of size effect, and the theory is comprehensively reviewed from the sharp macro-crack, surface flaw, stress redistribution, energy release, spatial correlation, and dimension of concrete aggregates.
A concrete box girder model prestressed with externally CFRP tendons was cast,and the stress redistribution,deflection and crack development of the girder model were tested for 1001d under sustained uniform load.
By using an elastoplastic-fracture model describing the mechanical properties of concrete and foundation rock,the extent of crack zone in the dam-foundation interface,the variation in dam deformation and the stress redistribution of arch dam can be computed.
(2) Typical finite element models of stainless steel brazed joints are constructed. Stress distribution and its time-dependant features are calculated. The features of stress redistribution are obtained.
(3) Based on the results of the stress redistribution, factors affecting the strength of stainless steel brazed joints at high temperature are discussed. Optimized joint types for design are recommended.
Weldbonding is a new joining technique that combines the spot welding with the adhesive bonding method It was adopted more and more in recent years because of its many advantages However, the researches on this new technology are few especially on the long term stress and strength of the weldbonded structures A three dimensional viscoplastic finite element model of single lap weldbonded joint was developed in this paper to investigate its stress redistribution Some advice on joint design and material choice were discussed
1. Pre-stressed functions expanded the structure elastic scope, has adjusted the structure stress redistribution, reduced the amount of deflection distortion, enhanced the cracking load and the limited supporting capacity.
Based on the linear creep theory and deformation coordination principle, the calculation method and computing formulas about the inner force redistribution and the stress redistribution are investigated in this thesis, the validity of this method is demonstrated by comparison the calculated results with the tested results.
Through the test of three frame models and the full range analysis of forty frames, the peculiar properties of the stress redistribution in plastic stage in composite prestressed concrete frame has been discussed and the maximum allowable adjusting extent of moment in joint of such frame under vertical loading is suggested.
According to constitutive equation of masonry materials, and considering the indeterminacy of the structure of arch Jam, the State of stress redistribution when the masonry thin arch dam goes beyond the scope of elasticity is analysed by the elastic-plastic theory to reasonably analyse and correctly reflect the state of stress of it.
The coupling of the dynamic stress redistribution and the heterogeneity at different scales result in an inverse cascade of damage cluster size, which represents rapid coalescence of damage at the catastrophe transition.
We found that as damage accumulates, there is a stronger and stronger nonlinear increase in stress and the stress redistribution distance.
Therefore, it is surmised that the longer-range stress redistribution resulting from damage in heterogeneous media may be a plausible mechanism governing main shocks.
The stress redistribution in the heterogeneous-brittle medium implies a longer-range interaction than that in an elastic medium.
In order to understand long-range stress redistribution, we propose a linear-elastic but heterogeneous-brittle model.