Lumped Damage Mechanics

2015 ◽  
pp. 362-411
Keyword(s):  
Structural Analysis ◽  
Fracture Mechanics ◽  
Structural Damage ◽  
Damage Mechanics ◽  
Structural Behavior ◽  
Numerical Implementation ◽  
Plastic Range ◽  
Structural Collapse ◽  
Framed Structures ◽  
Damage And Fracture

As aforementioned, buildings in seismic zones must be designed to behave elastically under service loads or earthquakes of small intensity, and they can enter in the plastic range for events of intermediate intensity. Severe earthquakes are defined as those that are improbable but not impossible to happen during the lifetime of the structure. In these cases, structural damage, even damage that cannot be repaired, is allowed as long as there is no structural collapse. In order to design or certify safe structures, it is necessary to have computational tools that allow for the quantification of structural damage and that are able to describe structural behavior accurately near collapse. The elasto-plastic models present serious limitations in this sense. Damage and fracture mechanics represent a more rational option. The goal of this chapter is to describe how the concepts presented in Chapter 9 can be included in the mathematical models for the analysis of framed structures and its numerical implementation in structural analysis programs.

Coupling Analysis of Fracture Mechanics and Damage Mechanics for Fiber-Reinforced Asphalt Concrete Pavement

2006 ◽  
Author(s):  
Yazhen Sun ◽  
Jiemin Liu ◽  
Tianqing Yu
Keyword(s):  
Fracture Mechanics ◽  
Asphalt Concrete ◽  
Damage Mechanics ◽  
Concrete Pavement ◽  
Initial Surface ◽  
Fiber Reinforced ◽  
Coupling Analysis ◽  
Damage And Fracture ◽  
Comparison Of The Results ◽  
Asphalt Concrete Pavement

The initial damage and fracture zone are determined by the approach of coupling analysis of fracture mechanics and damage mechanics. An optimum fiber content of 0.2% in the asphalt concrete is proposed in comparison of the results obtained from composite theory with that obtained from the splitting tests. Crack growth with number of load cycles and fiber mass fraction of asphalt concrete pavement in which an initial surface crack of 4 cm length is included under cyclic temperature loading (-15°C) is simulated using damage mechanics theorem. By computing fatigue life, a new type of fiber-reinforced asphalt concrete pavement is developed.

scholarly journals Combining damage and fracture mechanics to model calving

2014 ◽  
Vol 8 (6) ◽  
pp. 2101-2117 ◽  
Author(s):  
J. Krug ◽  
J. Weiss ◽  
O. Gagliardini ◽  
G. Durand
Keyword(s):  
Fracture Mechanics ◽  
Damage Mechanics ◽  
Dynamic Equilibrium ◽  
Continuum Damage Mechanics ◽  
Model Parameters ◽  
Critical Surface ◽  
Linear Elastic ◽  
Damage And Fracture ◽  
Brittle Fractures ◽  
Long Timescales

Abstract. Calving of icebergs is a major negative component of polar ice-sheet mass balance. Here we present a new calving model relying on both continuum damage mechanics and linear elastic fracture mechanics. This combination accounts for both the slow sub-critical surface crevassing and the rapid propagation of crevasses when calving occurs. First, damage to the ice occurs over long timescales and enhances the viscous flow of ice. Then brittle fractures propagate downward, at very short timescales, when the ice body is considered as an elastic medium. The model was calibrated on Helheim Glacier, Southeast Greenland, a well-monitored glacier with fast-flowing outlet. This made it possible to identify sets of model parameters to enable a consistent response of the model and to produce a dynamic equilibrium in agreement with the observed stable position of the Helheim ice front between 1930 and today.

scholarly journals Combining damage and fracture mechanics to model calving

2014 ◽  
Vol 8 (1) ◽  
pp. 1111-1150 ◽  
Author(s):  
J. Krug ◽  
J. Weiss ◽  
O. Gagliardini ◽  
G. Durand
Keyword(s):  
Fracture Mechanics ◽  
Damage Mechanics ◽  
Dynamic Equilibrium ◽  
Continuum Damage Mechanics ◽  
Model Parameters ◽  
Critical Surface ◽  
Modeling Framework ◽  
Outlet Glacier ◽  
Damage And Fracture ◽  
Long Timescales

Abstract. Calving of icebergs is a major negative component of polar ice-sheet mass balance. We present a new calving modeling framework relying on both continuum damage mechanics and linear elastic fracture mechanics. This combination accounts for both the slow sub-critical surface crevassing and fast propagation of crevasses when calving occurs. First, damage of the ice occurs over long timescales and enhances the viscous flow of ice. Then brittle fracture propagation happens downward, over very short timescales, in ice considered as an elastic medium. The model is validated on Helheim Glacier, South-West Greenland, one of the most monitored fast-flowing outlet glacier. This allows to identify sets of model parameters giving a consistent response of the model and producing a dynamic equilibrium in agreement with observed stable position of the Helheim ice front between 1930 and today.

scholarly journals Combining damage and fracture mechanics to model calving

2014 ◽  
Vol 8 (2) ◽  
pp. 1631-1671 ◽  
Author(s):  
J. Krug ◽  
J. Weiss ◽  
O. Gagliardini ◽  
G. Durand
Keyword(s):  
Fracture Mechanics ◽  
Damage Mechanics ◽  
Dynamic Equilibrium ◽  
Continuum Damage Mechanics ◽  
Model Parameters ◽  
Critical Surface ◽  
Modeling Framework ◽  
Outlet Glacier ◽  
Damage And Fracture ◽  
Long Timescales

Abstract. Calving of icebergs is a major negative component of polar ice-sheet mass balance. We present a new calving modeling framework relying on both continuum damage mechanics and linear elastic fracture mechanics. This combination accounts for both the slow sub-critical surface crevassing and fast propagation of crevasses when calving occurs. First, damage of the ice occurs over long timescales and enhances the viscous flow of ice. Then brittle fracture propagation happens downward, over very short timescales, in ice considered as an elastic medium. The model is validated on Helheim Glacier, South-West Greenland, one of the most monitored fast-flowing outlet glacier. This allows to identify sets of model parameters giving a consistent response of the model and producing a dynamic equilibrium in agreement with observed stable position of the Helheim ice front between 1930 and today.

Limit State Philosophy in Pipeline Design

1987 ◽  
Vol 109 (1) ◽  
pp. 9-22 ◽  
Author(s):  
C. P. Ellinas ◽  
P. W. J. Raven ◽  
A. C. Walker ◽  
P. Davies
Keyword(s):  
Structural Analysis ◽  
Safety Factor ◽  
Current Knowledge ◽  
Limit State ◽  
Structural Behavior ◽  
Major Conclusion ◽  
Safety Factors ◽  
Suitable Framework ◽  
General Aspects ◽  
Pipeline Design

This paper considers the application of the limit state philosophy of structural analysis to pipeline design. General aspects of the philosophy are discussed and the approach to the evaluation of safety factors is reviewed. The paper further considers the various limit and serviceability states which would be relevant to a pipeline and reviews the various factors which may require consideration, before a code embodying the limit state philosophy could be formulated. A review of the state of current knowledge on various aspects of geometry and material characteristics, loading and structural behavior is presented. It is intended that such a review can be used as the basis for a larger study to provide guidance and data for the evaluation of rational levels of safety factor. The major conclusion reached by the authors is that a limit state philosophy would be valuable in providing a suitable framework, which may highlight the significant aspects of pipeline design and which can most easily accommodate new requirements and results obtained from research.

scholarly journals A bi-dissipative damage model for concrete

2015 ◽  
Vol 8 (1) ◽  
pp. 49-65
Author(s):  
J. J. C. Pituba ◽  
W. M. Pereira Júnior
Keyword(s):  
Reinforced Concrete ◽  
Structural Engineering ◽  
Damage Mechanics ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Concrete Material ◽  
Framed Structures ◽  
Energy Equivalence ◽  
Proposed Model ◽  
Damage Processes

This work deals with an improvement of an anisotropic damage model in order to analyze reinforced concrete structures submitted to reversal loading. The original constitutive model is based on the fundamental hypothesis of energy equivalence between real and continuous media following the concepts of the Continuum Damage Mechanics. The concrete is assumed as an initial elastic isotropic medium presenting anisotropy, permanent strains and bimodularity induced by damage evolution. In order to take into account the bimodularity, two damage tensors governing the rigidity in tension or compression regimes are introduced. However, the original model is not capable to simulate the influence of the previous damage processes in compression regimes. In order to avoid this problem, some conditions are introduced to simulate the damage unilateral effect. It has noted that the damage model is agreement with to micromechanical theory conditions when dealing to unilateral effect in concrete material. Finally, the proposed model is applied in the analyses of reinforced concrete framed structures submitted to reversal loading. These numerical applications show the good performance of the model and its potentialities to simulate practical problems in structural engineering.

Sign in / Sign up

Export Citation Format

Share Document