[雙語(yǔ)翻譯]--外文翻譯--三維空間應(yīng)用彌散裂紋法對(duì)大體積混凝土的性能影響（原文）

1、 1BEHAVIOR OF MASS CONCRETE USING SMEARED CRACK APPROACH IN THREE DIMENSIONAL PROBLEMS H. Mirzabozorg1and M. Ghaemian1 1Department of Civil Engineering, Sharif University of Technology, PO Box 11365-9313, Tehran, Iran

2、 ABSTRACT A smeared crack approach has been proposed to model the static and dynamic behavior of mass concrete in three-dimensional space. The proposed model simulates the tensile fracture on the mass concrete and cont

3、ains pre-softening behavior, softening initiation, fracture energy conservation and strain rate effects under dynamic loads. It was found that the proposed model gives excellent results and crack profiles comparing wi

4、th the available data under static loads. Morrow Point dam was analyzed including dam-reservoir interaction effects to consider its nonlinear seismic behavior. It was found that the resulted crack profiles are in good

5、agreement with the contour of maximum principal stresses and no numerical instability occurred during the analysis. 1 INTRODUCTION Several numerical models have been developed for seismic safety evaluation of concrete

6、dams in two and three-dimensional space. El-Aidi and Hall [1 and 2] considered the nonlinear seismic response of concrete gravity dams using the smeared crack model. It was found that the resulted crack profiles are u

7、nrealistic due to using the size reduced strength criterion (SRS) in the proposed smeared crack model. Vargas-Loli and Fenves [3] considered the seismic response of Pine Flat dam using the smeared crack model with the

8、 brittle fracture criterion. Bhattachrjee and Leger [4, 5 and 6] used a smeared crack model to analyze concrete gravity dams in static and dynamic loading conditions. Ghrib and Tinawi [7 and 8] used the damage mechani

9、cs theory in static and seismic analysis of concrete gravity dams. Hall [9] proposed a special smeared crack model to simulate nonlinear behavior of the dam body and vertical construction joins simultaneously. Ghaemi

10、an and Ghobarah [10] developed a solution scheme to analyze concrete gravity dams in seismic loads. This method is called staggered method. The developed method was used in nonlinear seismic analysis of concrete dams i

11、n two- dimensional space (Ghaemian and Ghobarah [11]). Guanglun et al. [12] used the smeared crack model developed in Bhattacharjee and Leger [4] with re-meshing capability. Ahmadi et al. [13] proposed a model to simul

12、ate the static and dynamic behavior of vertical construction joints in arch dams. Gunn [14 and 15] used the damage mechanics theory to consider the effect of nonlinear behavior of the dam body under static loads in thr

13、ee-dimensional problems. Espandar and Lotfi [16] compared the performance of the smeared crack model and elasto-plastic model to consider the nonlinear behavior of dam body in three-dimensional space. Mirzabozorg et al

14、. [17] extended the staggered displacement method developed in Ghaemian and Ghobarah [10] to solve the three dimensional coupled problems in time domain. Lotfi and Espandar [18] used a non-orthogonal smeared crack wit

15、h a discrete crack model to simulate the nonlinear behavior of dam body and vertical construction joins in arch dams, simultaneously. In the present article, a three-dimensional smeared crack approach is proposed to m

16、odel the tensile fracture in static and dynamic conditions. The proposed model includes various aspects to simulate the nonlinear behavior of mass concrete in concrete dams. 2 CONSTITUTIVE LAW OF MASS CONCRETE The rel

17、ationship of the stress and strain vectors at the pre-softening phase is given as: 3The concept used in damage mechanics theory presented in (Gunn [14 and 15]) has been employed to set up shear stiffness changes due to

18、softening phase. The shear re-tension factors in eqn (3) are determined as following: ( )? ? ?? ? ? ?? ? ? ?? + ?? + = 3 2 1 2 2 1 2 13 2 1 32 12 2 1 1 12 2 dd1 η η η υ η υη ε εε η η υηε εε η ε η υ β( )? ? ?? ? ? ?? ? ?

19、 ?? + ?? + = 3 2 1 2 3 2 3 21 3 2 13 23 3 2 2 23 2 dd1 η η η υ η υη ε εε η η υηε εε η ε η υ β( )? ? ?? ? ? ?? ? ? ?? + ?? + = 3 2 1 2 3 1 3 12 3 1 23 13 3 1 1 13 2 dd1 η η η υ η υη ε εε η η υηε εε η ε η υ β3 2 1 3 3 1 2

20、3 2 2 2 1 2 2 1 dd η η η υ η η υ η η υ η η υ ? ? ? ? =) 4 (The co-axial rotating crack model has been used to simulate the behavior of the cracked element. The crack closing/reopening criterion is based on the value of

21、principal strains in which the total strain can be decomposed into the two components of elastic and residual strain given as (Ghrib and Tinawi [7 and 8]). 3 FINITE ELEMENT IMPLEMENTATION OF THE PROPOSED MODEL In th

22、e present article, 20-node iso-parametric element has been used in finite element implementation. The stiffness matrix and all of the other related components have been computed based on 3*3*3 Gaussian integration poin

23、ts. All of the related algorithms and state determination of elements are based on the average response of the element which is computed with averaging the computed strains within Gaussian points. 4 NUMERICAL RESULTS

24、4.1 Example I: Scaled Concrete Gravity Dam under Indirect Displacement Control Two scaled down 1:40 of a typical concrete gravity dam subjected to equivalent hydraulic lateral loads were tested by Carpinteri et al. [19

25、]. The modulus of elasticity, Poisson's ration, tensile strength and specific fracture energy were reported to be 35.7GPa, 0.1, 3.6MPa and 184N/m, respectively. The tested system has been show in Figure 1. Figure

26、1: Scaled down 1:40 concrete gravity dam (Carpinteri et al. [19]) The crack mouth opening displacement (CMOD) was used as a control parameter adjusting the applied load. The model has 605 20-node iso-parametric elements