CN102628861B - Method for simulating temperature cracking value of mass concrete - Google Patents
Method for simulating temperature cracking value of mass concrete Download PDFInfo
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Abstract
The invention discloses a method for simulating the temperature cracking value of mass concrete. The method comprises the following steps of: I, establishing a physical model of concrete, wherein the physical model consists of aggregate and mortar; II, dispersing the physical model obtained in the step I into a series of physical units; III, inserting thickness interface units among the physical model units obtained in the step II to form a concrete mesoscopic model; IV, simulating the temperature field of concrete; and V, simulating the mesoscopic cracking process of the concrete model under the temperature field in the step IV by adopting a continuous-discrete coupling method. In the method, the shape and gradation of aggregate particles and the random distribution condition of the aggregate particles in a calculating domain are fully considered, so that the microstructure of concrete can be simulated more really, the generation, expansion and penetration of cracks in the mass concrete can be simulated more really, and an entire process ranging from small deformation to large deformation till destroy of a concrete material can be reflected.
Description
Technical field
The invention belongs to Hydraulic and Hydro-Power Engineering field, relate in particular to a kind of mass concrete temperature cracking method for numerical simulation.
Background technology
Along with the construction of the high arch dam of the multiple 300m level of recent year, massive concrete temperature cracks problem becomes increasingly conspicuous, and temperature cracks control of mass concrete problem becomes the focus that educational circles pays close attention to and discusses.In the work progress of concrete dam and run duration, in large volume concrete structural, tend to because the variation of temperature produces very large tension, so tend to occur crack in large volume concrete structural.If surface crack, can cause damage to concrete permanance, if the deep layer of developing into or penetrability crack, can affect the globality of xoncrete structure, the stress distribution of change structure and stress condition, thereby likely make concrete partial structurtes or even one-piece construction destroy, endanger very large.Therefore, concrete analysis on temperature stress, prevent the measure in crack, it is problem very important in large volume concrete structural design and construction, the Cracking Mechanism of research mass concrete under temperature load, safely etc. all significant to dam safety assessment, the construction of scientific guidance Dam Designs in Last, guarantee construction quality.
The heterogeneous composite material that concrete is made up of aggregate, mortar etc., wherein also exists many natural or artificial micro-cracks.Concrete cracking, essence is that the germinating, expansion, perforation of a micro-crack is until the process of overall unstability, being one develops and leads to mutation process to the gradual evolution of gross fracture from microscopic damage, therefore, only cannot truly reflect the anisotropic property of concrete heterogeneous compound composition and material from macroscopic perspective, also cannot react existence, expansion, extension and the perforation process of microfracture.At present, Chinese scholars about the research of temperature cracking aspect mainly based on macro-level, concrete is regarded as to the material of single average and studied, cannot reflect really concrete microscopical structure, naturally also just cannot obtain real temperature cracking behavior.Only a few scholar has launched research aspect Meso-level Structure of Concrete, general by stochastic mechanics characteristic model, consider the randomness that the each phase component mechanical characteristic of concrete distributes, but fail to consider shape, grating and the stochastic distribution in computational fields of particles of aggregates, and all only limit to the research of small size concrete sample.And aspect the thin sight Cracking Mechanism of massive concrete temperature cracks, dynamic expansion analogy method, not relevant achievement in research also both at home and abroad so far.
Summary of the invention
The object of this invention is to provide a kind of mass concrete temperature cracking method for numerical simulation, the method can be predicted under temperature load accurately, easily, the process of concrete from microscopic damage to cracking.
A kind of Temperature Controlling of Mass Concrete cracking method for numerical simulation of the present invention, comprises the following steps:
Step 1, sets up concrete solid model, and described solid model is made up of aggregate and mortar;
Step 2, by discrete step 1 gained solid model be a series of solid elements;
Step 3 is inserted with thickness boundary element and carefully sees model to form concrete between the each solid element of step 2 gained;
Step 4, the temperature field of simulation concrete;
Step 5, adopts the thin sight cracking process of continuously-discrete coupling process simulation concrete model under the temperature field of step 4.
In described step 1, the aggregate of solid model is adopted with the following method and is generated:
First according to the grading curve of aggregate, the particle diameter of aggregate is divided into several particle size interval, then build particles of aggregates one by one for each particle size interval until particles of aggregates content meets the grating requirement of grading curve, above-mentionedly build particles of aggregates for each particle size interval and comprise successively following sub-step:
1) according to an ellipse of the random generation of the bound of particle size interval, oval semiaxis a, the b that generate are respectively: a=r
1+ (r
2-r
1) rand1, b=r
1+ (r
2-r
1) rand2, wherein: r
1for the lower limit of particle size interval; r
2for the upper limit of particle size interval; Rand1, rand2 are equally distributed independent random number in interval [0,1];
2) random cloth summit on step 1 gained ellipse, and each summit is connected to form to convex polygon in turn, gained convex polygon is a particles of aggregates M
j, wherein, the numbering that j is particles of aggregates, its initial value is 1;
3) the quantity m of the judgement particles of aggregates that generates, if m is 1, after j being added to 1, circulation execution step 1); Otherwise, execution step 4);
4) by particles of aggregates M
jcarry out one by one whether crossing judgement with all particless of aggregates that generate before, as long as particles of aggregates M
jcrossing with arbitrary particles of aggregates existence, delete particles of aggregates M
j, then circulation execution step 1; Otherwise, j is added to 1 rear recycle execution step 1).
Above-mentioned steps 2) on each ellipse the numerical value n on summit be n=[n
min+ (n
max-n
min) rand+1], wherein, rand is equally distributed independent random number in interval [0,1], n
min, n
maxcan be according to the true form value of particle; Each summit on ellipse is numbered in turn, i apex coordinate (x
i, y
i) be
wherein, i ∈ [1, n], and i is integer; (x
0, y
0) be oval central coordinate of circle;
be the position angle in polar coordinate system, in [0,2 π] interval, be uniformly distributed.
Above-mentioned steps 4) in judge between particles of aggregates, whether have the crossing step that further comprises:
1. relatively the distance of center circle of the first particles of aggregates and the second particles of aggregates place ellipse from major semi-axis sum, if distance of center circle is from being greater than major semi-axis sum, two particless of aggregates are non-intersect; Otherwise, execution step 2);
2. judge whether the first particles of aggregates exists a limit, make the second all summits of particles of aggregates all in this limit one side, and Gai limit, the center of circle opposite side of the first particles of aggregates place ellipse, if existed, two particless of aggregates are non-intersect; Otherwise two particless of aggregates intersect.
In step 1, the mortar of solid model is adopted simulation with the following method:
Set up a rectangle according to concrete size, from rectangle, deduct particles of aggregates, obtain mortar.
In step 2, adopt triangular prism shaped grid to carry out discrete to solid model.
In step 3, between each solid element, be inserted with thickness boundary element and further comprise following sub-step:
1, between the each solid element of step 2 gained, insert boundary element, this step is specially:
First, record in concrete solid model the original number of node under each solid element and solid element, node under each solid element and solid element is renumberd, make between solid element without common points, obtain new solid model, and set up each solid element and the corresponding relation of affiliated node in novel entities model and original solid model thereof; Then, search for all solid elements that have adjacent surface in original solid model, and record the numbering of every group of adjacent entities unit and adjacent surface; Then, in novel entities model, find out respectively at corresponding every group of adjacent entities unit and adjacent surface with it, and record eight node serial numbers on two adjacent surfaces; Finally, eight nodes on two adjacent surfaces just form boundary element;
2, on boundary element basis, generate and have thickness boundary element, this step is specially:
After each solid element is dwindled centered by the centre of form, connect eight nodes on solid element adjacent surface and be thickness boundary element.
It in step 4, is the temperature field that adopts Continuous medium FEM method simulation concrete.
In step 5, continuously-discrete coupling analytical method is specially:
Suppose under temperature load, concrete damage and fracture have occurred over just on thickness boundary element, only there is elastic deformation in solid element, adopt cohesive zone model to describe the stress and the deformation relationship that there are thickness boundary element, adopt and be with the Mohr-Coulomb criterion of breaking as the failure criteria that has thickness boundary element; When there being the stress state of thickness boundary element to meet after failure criteria, adopt the linear damage evolutionary model based on energy to failure to simulate the failure procedure that has thickness boundary element; After having thickness boundary element to lose efficacy, adopt linear rigidity contact model to simulate the contact relation of solid element.
Compared with prior art, tool of the present invention has the following advantages and beneficial effect:
The inventive method has taken into full account shape, grating and the stochastic distribution situation in computational fields of particles of aggregates, the microscopical structure of simulation concrete more truly, thereby can simulate more really germinating, the expansion of crackle in mass concrete and connect, can reflect concrete material from small deformation to large deformation until the overall process of destroying.
Brief description of the drawings
Fig. 1 is the particles of aggregates schematic diagram generating in concrete enforcement;
Fig. 2 is the mortar schematic diagram generating in concrete enforcement;
Fig. 3 is the discrete schematic diagram of solid model in concrete enforcement;
Fig. 4 is that in concrete enforcement, gained has thickness boundary element and solid element schematic diagram;
Concrete temperature field when Fig. 5 is 5 DEG C for cold wave temperature drop amplitude in specifically implementing;
Fig. 6 is the temperature field of concrete block when cold wave temperature drop amplitude is 10 DEG C in concrete enforcement;
Fig. 7 is sprouting and the mises stress schematic diagram of crackle in concrete in concrete enforcement;
Fig. 8 is expansion and the mises stress schematic diagram of crackle in concrete in concrete enforcement;
Fig. 9 is extension and the mises stress schematic diagram of crackle in concrete in concrete enforcement;
Figure 10 is the final cracking of concrete and mises stress schematic diagram in concrete enforcement;
Figure 11 is the position relationship schematic diagram of crackle and particles of aggregates in concrete enforcement.
Embodiment
The inventive method is taking into full account on the basis of the shape of particles of aggregates, grating and the stochastic distribution situation in computational fields, the concrete solid model of model, and this solid model is made up of aggregate and mortar, is used for the two-phase microscopical structure of simulation concrete; Then, by discrete solid model be a series of solid elements; Then, between each solid element, be inserted with thickness boundary element to form concrete model; Finally adopt continuously-discrete coupling process to simulate the thin sight cracking process of thickness boundary element under temperature field.
Further illustrate the present invention below in conjunction with the drawings and specific embodiments.
A kind of mass concrete temperature cracking method for numerical simulation that the present invention proposes, concrete steps are as follows:
Step 1, sets up concrete solid model, and this solid model is made up of aggregate and mortar.
1. the generation of aggregate in solid model
Aggregate in concrete, is generally formed by boulder fragmentation, is shaped as male type, and meets certain grain composition and content.The present invention uses stochastic simulation technology to generate the random particles of aggregates of shape and allows each particles of aggregates stochastic distribution in space.
While generating aggregate, first according to the grading curve of aggregate, particles of aggregates is divided into some groups of particle size interval, determine the bound of every group of particle size interval, generate from big to small the particles of aggregates in every group of particle size interval until particles of aggregates content meets the grating requirement of grading curve by particle size interval.In the time containing a large amount of fine aggregate, if the complete grading curve of simulation aggregate, need so the number of particles of aggregates of simulation will be very huge, counting yield is reduced greatly, therefore,, in order to improve counting yield, grading curve can be carried out to truncation in this case, for example, particle diameter in grading curve is less than to the particle that the particle particle diameter of 10mm is 10mm and carries out equivalent replacement.In order to reflect irregular form and the outer convexity of the particles of aggregates in concrete, on the ellipse generating, random cloth summit, connects convex polygon to represent particles of aggregates in then each summit being connected to form in turn.
In this concrete enforcement, aggregate adopts following ten thousand methods to generate:
First according to the grading curve of aggregate, the particle diameter of aggregate is divided into several particle size interval, then build particles of aggregates one by one for each particle size interval until particles of aggregates content meets the grating requirement of grading curve, above-mentionedly build particles of aggregates for each particle size interval and comprise successively following sub-step:
1) according to an ellipse of the random generation of the bound of particle size interval, oval semiaxis a, the b that generate are respectively: a=r
1+ (r
2-r
1) rand1, b=r
1+ (r
2-r
1) rand2, wherein: r
1for the lower limit of particle size interval; r
2for the upper limit of particle size interval; Rand1, rand2 are equally distributed independent random number in interval [0,1], that is, rand1, rand2 get in [0,1] in the probability of any numerical value be impartial.
2) in step 1) random cloth summit on gained ellipse, and each summit is connected to form to convex polygon in turn, gained convex polygon is a particles of aggregates M
j, wherein, the numbering that j is particles of aggregates, its initial value is 1.
For the particles of aggregates shape that ensures to obtain has enough randomness, on ellipse, the cloth number of vertex n of institute is at [n
min, n
max] between be uniformly distributed:
n＝[n
min+(n
max-n
min)rand+1] (1)
In formula (1):
Rand is equally distributed independent random number in interval [0,1];
N
min, n
maxaccording to the true form value of particles of aggregates, n in this concrete enforcement
minget 4, n
maxget 10.
Adopt polar coordinates to determine the position on institute's cloth summit on ellipse, the summit of n on ellipse is numbered in turn to i apex coordinate (x
i, y
i) be:
In formula (2):
I ∈ [1, n], and i is integer;
(x
0, y
0) be oval central coordinate of circle;
be the position angle in polar coordinate system, in [0,2 π], be uniformly distributed.
Determine behind the position on oval upper n summit, by each summit be connected to form in turn ellipse in connect convex polygon, this convex polygon is a particles of aggregates.
3) the quantity m of the judgement particles of aggregates that generates, if m is 1, after j being added to 1, circulation execution step 1); Otherwise, execution step 4).
4) by particles of aggregates M
jwhether all particless of aggregates that before generate intersect judgement one by one, as long as particles of aggregates M
jcrossing with arbitrary particles of aggregates existence, delete particles of aggregates M
j, then circulation execution step 1) and regenerate particles of aggregates M
j; Otherwise, j is added to 1 rear recycle execution step 1), generate new particles of aggregates M
j+1.
Between particles of aggregates in actual concrete, there will not be and intersect phenomenon, therefore, in the process of establishing of aggregate model, particles of aggregates of every generation, all need to judge that whether this particles of aggregates is crossing with all particless of aggregates that generate before, if intersect, need crossing particles of aggregates to regenerate.
In this specific embodiment, adopt judge with the following method between two particless of aggregates, whether exist crossing:
1. relatively the distance of center circle of the first particles of aggregates and the second particles of aggregates place ellipse from major semi-axis sum, if distance of center circle is from being greater than major semi-axis sum, two particless of aggregates are non-intersect; Otherwise execution step 2.;
2. judge whether the first particles of aggregates exists a limit, make the second all summits of particles of aggregates all in this limit one side, and Gai limit, the center of circle opposite side of the first particles of aggregates place ellipse, if existed, two particless of aggregates are non-intersect; Otherwise two particless of aggregates intersect.
Fig. 1 is the particles of aggregates of the single grating of 20～40mm of generation in this concrete enforcement, and granule content is 40%.
2. the simulation of mortar in solid model
The generation of mortar, this concrete enforcement is the rectangle of setting up a wide 1m, high 0.5cm, deducts particles of aggregates from rectangle, obtains mortar, specifically as shown in Figure 2.
Step 2, by discrete solid model be a series of solid elements.
In this concrete enforcement, adopt triangular prism shaped grid to carry out solid model discrete, specifically: first, adopt triangular mesh to carry out discrete to solid model; Then the certain thickness that triangular mesh stretched, has completed discrete to solid model of triangular prism shaped grid.Figure 3 shows that and adopt said method by schematic diagram discrete solid model, as shown in the figure, whole solid model is discrete is 2140 solid elements, and wherein, aggregate unit has 732, and mortar unit has 1408.
Step 3 is inserted with thickness boundary element and carefully sees model to form concrete between each solid element.
This step comprises two parts: between each solid element, inserting boundary element and generating and have thickness boundary element on boundary element basis.
1, between each solid element, insert boundary element:
In this concrete enforcement, be to adopt between each solid element, to insert with the following method boundary element:
First, the solid element in concrete solid model is traveled through, record solid element and affiliated node serial number thereof.
Then, each solid element and affiliated node thereof are renumberd, and each solid element has separately 6 nodes, makes between each solid element without common points, obtain new solid model, and set up each solid element and the corresponding relation of affiliated node in novel entities model and original solid model thereof.
Then, search for all solid elements that have adjacent surface in original solid model, and record the numbering of every group of adjacent entities unit and adjacent surface.In novel entities model, find out respectively at corresponding every group of adjacent entities unit and adjacent surface with it, and record eight node serial numbers on two adjacent surfaces.
Finally, eight nodes on two adjacent surfaces just form boundary element.
2, on boundary element basis, generate and have thickness boundary element:
In the present invention, generate and have the basic thought of thickness boundary element to be: solid element is dwindled centered by its centre of form, between solid element and solid element, form gap, now two of solid element adjacent surfaces are separated from each other, and connect eight nodes on solid element adjacent surface and are formed with thickness boundary element.Concrete grammar is as follows:
The centre of form coordinate of solid element is:
xcor＝centrx(k)
(3)
ycor＝centry(k)
zcor＝centrz(k)
In formula (3):
Xcor, ycor, the centre of form coordinate that zcor is solid element;
K is element number.
The thickness of supposing to have thickness boundary element be solid element size T doubly because boundary element is for simulation fracture path, while only having thickness very little, could not affect concrete bulk property, so T gets a smaller value, for example 0.01,0.02.After solid element dwindles centered by the centre of form, on solid element, each node coordinate is:
nx＝nx
ki-(nx
ki-xcor)×T
(4)
ny＝ny
ki-(ny
ki-ycor)×T
nz＝nz
ki
In formula (4):
Nx
ki, ny
ki, nz
kiit is the coordinate (i=1,2,3,5,6,7) that is numbered i the node of solid element of k;
Nx, ny, nz is that the solid element that is numbered k dwindles the coordinate of i node afterwards.
Node coordinate after recording solid element and dwindling, connects eight nodes on adjacent surface and has been thickness boundary element.
Figure 4 shows that in this concrete enforcement and have thickness boundary element and solid element schematic diagram.
Step 4, the temperature field of simulation concrete:
In this specific embodiment, adopt the temperature field of Continuous medium FEM method simulation concrete, specific as follows:
According to the parameter shown in table 1, simulate concrete temperature field, concrete upper surface is first kind heat radiation border, remaining surface is adiabatic border.Adopting preceding method simulated condition is wide 1m, the early-age concrete piece of the high 0.5 meter temperature variation under cold wave, suppose that cold wave operating mode is 1 DEG C/h for temperature in 10h evenly reduces by 10 DEG C and temperature drop rate, temperature reduces by 5 DEG C time concrete temperature field, and as shown in Figure 5, when temperature reduces by 10 DEG C, concrete temperature field as shown in Figure 6.
Table 1 concrete parameters
Step 5, adopts the thin sight cracking process of continuously-discrete coupling process simulation concrete model under temperature field.
Adopting in the continuously-thin sight cracking process of discrete coupling process simulation concrete under temperature field, the present invention has done following supposition:
1) concrete is considered as to gelling particulate material, in the time of numerical simulation by its discrete be solid element and have thickness boundary element, solid element corresponding to particles of aggregates and mortar particle, to have thickness boundary element corresponding to intergranular glued layer;
2) concrete damage and fracture have occurred over just on thickness boundary element, and the Mohr-Coulomb criterion that the stretching of employing band is blocked is as the failure criteria of boundary element, and elastic deformation only occurs solid element;
3) do not consider there is the interaction between thickness boundary element normal direction and tangential stress, when the stress state of thickness boundary element meets after failure criteria, there is the rigidity of thickness boundary element to decline gradually, load-bearing capacity reduces, when stiffness degradation is to 0 time, there is thickness boundary element complete failure;
4) the thickness boundary element that has losing efficacy is deleted from concrete model, original by there being the connected solid element of thickness boundary element to come in contact relation, after all having thickness boundary element to lose efficacy, concrete is converted into discrete discrete material completely.
In this concrete enforcement, adopt cohesive zone model to describe to have normal direction, the tangential stress of thickness boundary element with open, relation between sliding deformation: in the starting stage of loading, have between the stress of thickness boundary element and relative displacement and meet linear relationship, along with the carrying out of temperature loading, there is the stress state of thickness boundary element to reach after failure criteria, there is the rigidity of thickness boundary element to decline gradually, load-bearing capacity reduces, and when stiffness degradation is to 0 time, has thickness boundary element complete failure.
The Mohr-Coulomb criterion that the stretching of employing band is blocked is as the failure criteria that has thickness boundary element, after having the normal stress of thickness boundary element to exceed tensile strength, there is fail in tension, and the tangential stress that has thickness boundary element exceedes shearing strength shear failure occurs, in this concrete enforcement, pay the utmost attention to the fail in tension of thickness boundary element, if have thickness boundary element that fail in tension and shear failure occur, this element be used as to fail in tension simultaneously.
When having after thickness boundary element complete failure, this inefficacy has the connected solid element of thickness boundary element to come in contact relation, in this concrete enforcement, adopts linear rigidity contact model to simulate the contact relation of solid element.
Simulate in step 4 on the basis, temperature field obtaining, calculate stress intensity and the prediction cracking situation of concrete under cold wave operating mode, specific as follows:
Taking step 3 gained concrete model as basis, in concrete, each phase material attribute is according to the parameter setting in table 2 and table 3, the constraint condition of setting concrete model is that surface, left and right vertical constraint, upper surface are free, lower surface retrains entirely, whole computation process is divided into N analysis portion (this specific embodiment is got N=100), calculates the stress state of concrete under temperature load.
For this concrete enforcement, in the time that temperature decreases by 1.4 DEG C, concrete block surface starts to crack, and Fig. 7-10 are sprouting, the expansion process of expanding, extend to final cracking and the major principal stress schematic diagram of concrete cracks; Figure 11 is the position relationship schematic diagram of crackle and particles of aggregates, and in figure, crackle all occurs in mortar or on the interface of mortar and aggregate, seldom occurs in aggregate.
Table 2 Stress calculation parameter
Table 3 has thickness boundary element parameter
Claims (8)
1. a Temperature Controlling of Mass Concrete cracking method for numerical simulation, is characterized in that, comprises the following steps:
Step 1, sets up concrete solid model, and described solid model is made up of aggregate and mortar;
Step 2, by discrete step 1 gained solid model be a series of solid elements;
Step 3 is inserted with thickness boundary element and carefully sees model to form concrete between the each solid element of step 2 gained;
Step 4, the temperature field of simulation concrete;
Step 5, adopts the thin sight cracking process of continuously-discrete coupling process simulation concrete model under the temperature field of step 4;
In step 1, the aggregate of solid model is adopted with the following method and is generated:
First according to the grading curve of aggregate, the particle diameter of aggregate is divided into several particle size interval, then build particles of aggregates one by one for each particle size interval until particles of aggregates content meets the grating requirement of grading curve, above-mentionedly build particles of aggregates for each particle size interval and comprise successively following sub-step:
1) according to an ellipse of the random generation of the bound of particle size interval, oval semiaxis a, the b that generate are respectively: a=r
1+ (r
2-r
1) rand1, b=r
1+ (r
2-r
1) rand2, wherein: r
1for the lower limit of particle size interval; r
2for the upper limit of particle size interval; Rand1, rand2 are equally distributed independent random number in interval [0,1];
2) in step 1) random cloth summit on gained ellipse, and each summit is connected to form to convex polygon in turn, gained convex polygon is a particles of aggregates M
j, wherein, the numbering that j is particles of aggregates, its initial value is 1;
3) the quantity m of the judgement particles of aggregates that generates, if m is 1, after j being added to 1, circulation execution step 1); Otherwise, execution step 4);
4) by particles of aggregates M
jcarry out one by one whether crossing judgement with all particless of aggregates that generate before, as long as particles of aggregates M
jcrossing with arbitrary particles of aggregates existence, delete particles of aggregates M
j, then circulation execution step 1); Otherwise, j is added to 1 rear recycle execution step 1).
2. Temperature Controlling of Mass Concrete cracking method for numerical simulation according to claim 1, is characterized in that:
Described step 2) in the numerical value n on oval upper summit be n=[n
min+ (n
max-n
min) rand+1], wherein, rand is equally distributed independent random number in interval [0,1], n
min, n
maxcan be according to the true form value of particle; Each summit on ellipse is numbered in turn, i apex coordinate (x
i, y
i) be
wherein, i ∈ [1, n], and i is integer; (x
0, y
0) be oval central coordinate of circle;
be the position angle in polar coordinate system, in [0,2 π] interval, be uniformly distributed.
3. Temperature Controlling of Mass Concrete cracking method for numerical simulation according to claim 1, is characterized in that:
Described step 4) in judge between particles of aggregates, whether have the crossing step that further comprises:
1. relatively the distance of center circle of the first particles of aggregates and the second particles of aggregates place ellipse from major semi-axis sum, if distance of center circle is from being greater than major semi-axis sum, two particless of aggregates are non-intersect; Otherwise, execution step 2);
2. judge whether the first particles of aggregates exists a limit, make the second all summits of particles of aggregates all in this limit one side, and Gai limit, the center of circle opposite side of the first particles of aggregates place ellipse, if existed, two particless of aggregates are non-intersect; Otherwise two particless of aggregates intersect.
4. Temperature Controlling of Mass Concrete cracking method for numerical simulation according to claim 1, is characterized in that:
In described step 1, the mortar of solid model is adopted simulation with the following method:
Set up a rectangle according to concrete size, from rectangle, deduct particles of aggregates, obtain mortar.
5. Temperature Controlling of Mass Concrete cracking method for numerical simulation according to claim 1, is characterized in that:
In described step 2, adopt triangular prism shaped grid to carry out discrete to solid model.
6. Temperature Controlling of Mass Concrete cracking method for numerical simulation according to claim 1, is characterized in that:
In described step 3, between each solid element, be inserted with thickness boundary element and further comprise following sub-step:
1) between the each solid element of step 2 gained, insert boundary element, this step is specially:
First, record in concrete solid model the original number of node under each solid element and solid element, node under each solid element and solid element is renumberd, make between solid element without common points, obtain new solid model, and set up each solid element and the corresponding relation of affiliated node in novel entities model and original solid model thereof; Then, search for all solid elements that have adjacent surface in original solid model, and record the numbering of every group of adjacent entities unit and adjacent surface; Then, in novel entities model, find out respectively at corresponding every group of adjacent entities unit and adjacent surface with it, and record eight node serial numbers on two adjacent surfaces; Finally, eight nodes on two adjacent surfaces just form boundary element;
2) on boundary element basis, generate and have thickness boundary element, this step is specially:
After each solid element is dwindled centered by the centre of form, connect eight nodes on solid element adjacent surface and be thickness boundary element.
7. Temperature Controlling of Mass Concrete cracking method for numerical simulation according to claim 1, is characterized in that:
It in described step 4, is the temperature field that adopts Continuous medium FEM method simulation concrete.
8. Temperature Controlling of Mass Concrete cracking method for numerical simulation according to claim 1, is characterized in that:
In described step 5, continuously-discrete coupling analytical method is specially:
Suppose under temperature load, concrete damage and fracture have occurred over just on thickness boundary element, only there is elastic deformation in solid element, adopt cohesive zone model to describe the stress and the deformation relationship that there are thickness boundary element, adopt and be with the Mohr-Coulomb criterion of breaking as the failure criteria that has thickness boundary element; When there being the stress state of thickness boundary element to meet after failure criteria, adopt the linear damage evolutionary model based on energy to failure to simulate the failure procedure that has thickness boundary element; After having thickness boundary element to lose efficacy, adopt linear rigidity contact model to simulate the contact relation of solid element.
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