CN103177194A - Discrete element analysis method of slender type metal tube drug tamping state - Google Patents

Abstract

The invention discloses a discrete element analysis method of slender type metal tube drug tamping state, and relates to the field of computer model analysis. The method comprises the following steps: 1) establishing a slender type metal tube model; 2) establishing a drug particle feeding model; 3) establishing a drug particle model; 4) simulating of the tamping action of the slender type metal tube; 5) observing the movement, of the drug particles in the slender type metal tube and the drug particle density change process in the tamping action in simulation mode by using the established discrete element model.

Description

A kind of discrete element analytical approach of slender type metal tube medicament compacting state

Technical field

The present invention relates to the computer simulation analysis field, particularly a kind of discrete element analytical approach to slender type metal tube medicament compacting process simulation.

Background technology

The compacting of slender type metal tube powder granule is the produce difficult point of priming system, priming system is higher to pharmacy particle density requirements in the slender type metal tube, uniformly the compacted density of slender type metal tube powder granule is the key factor that affects the priming system quality, can guarantee that the index such as line density satisfies the priming system quality requirements.The priming system of China still adopts the manual production pattern of single mode single-shot at present, and under this production model, exist following problem: (1) homogeneity of product is poor; (2) labour intensity is high, production efficiency is low; (3) there is health and safety hidden danger in operating personnel.For these problems, take vertical impact vibrating compacting principle as the basis, developed the tamping unit based on impact shock, this device utilizes the self gravitation of pharmacy particle to load, by the vibratory impulse effect on vertical direction, pharmacy particle is rearranged, to reach the purpose that improves the powder charge packing.This tamping unit has solved the poor problem of homogeneity of product, has reduced labour intensity, has improved production efficiency, has realized simultaneously man-machine isolation completely, has ensured operating personnel's health and safety.

But in the tamping unit operational process, can't observe motion, the pharmacy particle variable density process of the inner pharmacy particle of slender type metal tube in the compacting action.The discrete element method is the angle from particle, discloses the essence of macroscopic motion from microcosmic angle, provides effective solution route for solving problems.The combination of limited discrete unit regarded system unit as by the discrete element model, acting force between assuming unit is directly proportional to relative shift between them, then use Newton second law and set up the equation of motion, adopt at last central difference method to carry out explicit iterative, predict the motor behavior of Loose Bodies, can the clear principle of recognizing the various phenomenons in practical engineering application of let us.

At present, the discrete element method has in fields such as ground, mining and metallurgy, agricultural, chemical industry, pharmacy and environment widely to be used, but studies for the discrete element analysis of slender type metal tube medicament compacting state and nobody.

Summary of the invention

Purpose of the present invention just is to provide a kind of discrete element analytical approach of slender type metal tube medicament compacting state, and it can simulate motion and the pharmacy particle variable density process of the inner pharmacy particle of slender type metal tube in the compacting action.

The objective of the invention is to realize by such technical scheme, the concrete analysis step is as follows:

1) set up slender type metal tube model, adopt the hollow form cylindrical wall to simulate in the face of the slender type metal tube, the effective side of column type metope is cylindrical metope inwall, sets up the bottom metope bottom cylindrical metope plug is simulated, and the limited side of bottom metope is set up;

2) set up the reinforced model of pharmacy particle, adopt the funnel-form metope that the reinforced model of pharmacy particle is simulated, its effective side is funnel-form metope inwall, and sets the boundary condition that it generates for pharmacy particle;

3) according to step 2) in the pharmacy particle that obtains generate boundary condition, setting up linear contact stiffness model simulates the pharmacy particle model, can generate several times particle, each particle attribute that generates is identical, pharmacy particle model initial density and actual loose shape pharmacy particle density is set approaches;

4) carry out slender type metal tube compacting action simulation;

5) utilize the discrete element model that step 1) to step 4) is set up to tamp emulation, particle porosity when observing inner pharmacy particle motion and differing heights in simulation process, and adopt factor of porosity as the parameter index of pharmacy particle even density degree after weighing the compacting action and completing, inner each height pharmacy particle density uniformity of slender type metal tube after the checking compacting is completed, thus determine best compacting number of times and best compacting height.

Further, step 2) the boundary condition judgment formula of Chinese medicine particle generation is:

R_xy+r≤R_lim

-R_upper≤x≤R_upper

-R_upper≤y≤R_upper

H_cylinder≤z≤H+H_cylinder

Wherein, generating the particle center-of-mass coordinate is (x, y, z), particle radius is r, the reinforced model height of pharmacy particle is H, the upper opening radius is R_upper, and the lower openings radius is R_bottom, and slender type metal tube model height is H_cylinder, particle barycenter and z axle base are R_xy, limit radius R _ lim that the particle of same z axle height is allowed to generate.

Further, setting up linear contact stiffness model described in step 3) to the concrete grammar of pharmacy particle model is:

Make the contact force that firmly can calculate two Interaction between particles with the displacement Indentation Law:

$F_n^c=K_n{U}_{n}n$

In formula, Be the normal direction contact force; K _nBe the normal stiffness coefficient; U _nBe the normal direction contact displacement; N is unit normal vector;

$\mathrm{\Δ}{F}_s^c=k_s\mathrm{\Δ}{U}_s$

$F_s^c=F_{\mathrm{os}}^c+\mathrm{\Δ}{F}_s^c$

In formula, K _sBe tangential contact stiffness; △ U _sBe relative tangential displacement increment;

Be tangential contact force increment;

Tangential contact force for current time step;

Go on foot tangential contact force when last, so the suffered F that makes a concerted effort of particle is:

$F=F_n^c+F_s^c$

Can use Newton second law to set up the equation of motion according to the situation of making a concerted effort of particle:

F=ma。

Further, the metal tube of slender type described in step 4) compacting action simulation includes two stages:

4-1) the freely falling body stage of pharmacy particle;

4-2) pharmacy particle bottom compacting acting force applies;

Described compacting action can be identified bottom pharmacy particle layer, and the compacting action frequency, freely fall low clearance and compacting power is all adjustable.

Further, tamp emulation and observation in step 5) and include two stages:

5-1) initial equilibrium conditions emulation and observation, initial equilibrium conditions is initial equilibrium state after reinforced;

Balance emulation and observation after 5-2) the compacting action is completed.

Owing to having adopted technique scheme, the present invention has advantages of as follows:

1, the present invention utilizes motion and the pharmacy particle variable density process of the inner pharmacy particle of slender type metal tube in computer simulation compacting action, for the tamping unit compacting technique based on impact shock provides the performable theory foundation;

2, realized that the simulation of moving for the inner pharmacy particle of slender type metal tube in the compacting action is visual;

3, by emulation and observation, can determine best compacting number of times and best compacting height, improve the effect of actual compacting technique.

Other advantages of the present invention, target and feature will be set forth to a certain extent in the following description, and to a certain extent, based on being apparent to those skilled in the art to investigating hereinafter, perhaps can be instructed from the practice of the present invention.Target of the present invention and other advantages can realize and obtain by following instructions and claims.

Description of drawings

Description of drawings of the present invention is as follows.

Fig. 1 is the schematic flow sheet of slender type metal tube medicament compacting state discrete element analytical approach;

Fig. 2 is slender type metal tube model demonstration figure;

Fig. 3 is slender type metal tube model;

Fig. 4 is the reinforced model boundary condition of pharmacy particle;

Fig. 5 is the reinforced model boundary condition sectional drawing of pharmacy particle;

Fig. 6 is the reinforced model of pharmacy particle;

Fig. 7 is pharmacy particle model demonstration figure;

Fig. 8 is the pharmacy particle model;

Fig. 9 is the computation cycles process;

Granular model after four reinforced compactings of Figure 10 are completed;

Figure 11 is 6 and measures ball factor of porosity change curve;

Measure ball factor of porosity change curve No. 1 after ten compacting processing simulations of Figure 12;

Figure 13 tamps the factor of porosity change curve of height 250mm;

Figure 14 tamps the factor of porosity change curve of height 300mm;

Figure 15 tamps the factor of porosity change curve of height 350mm;

Embodiment

The invention will be further described below in conjunction with drawings and Examples.

A kind of discrete element analytical approach of slender type metal tube medicament compacting state comprises: the 1) foundation of slender type metal tube model; 2) foundation of the reinforced model of pharmacy particle; 3) foundation of pharmacy particle model; 4) slender type metal tube compacting action simulation is set up; 5) use motion, the pharmacy particle variable density process that the discrete element modeling of setting up is observed the inner pharmacy particle of slender type metal tube in the compacting action.

Discrete element analytical approach of the present invention as shown in Figure 1.

The compacting action is mainly the Vertical Free falling bodies.By vertical cylinder, the slender type metal tube is promoted to certain altitude, by gas pawl clamping slender type metal tube, guarantees the elemental height of freely falling body, unclamp the freely falling body that to realize the slender type metal tube after the gas pawl.Therefore the present invention sets forth from following five parts:

1), the foundation of slender type metal tube model

Set up cylindrical metope realization to the simulation of slender type metal tube, cylindrical metope is hollow form; It is inner that the effective side of cylindrical metope is pointed to cylindrical metope, the interaction between realization and cylindrical metope and internal particle; Set up bottom metope realization to the simulation of plug bottom cylindrical metope; Effective side of bottom metope up, realize and bottom metope and internal particle between interaction; The slender type metal tube is yielding, so that its rigidity arranges the numbered magnitude is low than the bottom surface infinitepiston.Slender type metal tube model demonstration figure as shown in Figure 2; Slender type metal tube model as shown in Figure 3.

2), the foundation of the reinforced model of pharmacy particle

Set up the funnel-form metope and realize that funnel-form metope upper opening radius ratio lower openings radius is large to the simulation of the reinforced model of pharmacy particle, be positioned at slender type metal tube model top; It is inner that the effective side of funnel-form metope is pointed to the funnel-form metope, the interaction between realization and funnel-form metope and internal particle; The reinforced model of pharmacy particle is the boundary condition that pharmacy particle generates, and the border determination methods is as follows:

If generating the particle center-of-mass coordinate is (x, y, z), particle radius is r, and the reinforced model height of pharmacy particle is H, the upper opening radius is R_upper, the lower openings radius is R_bottom, and slender type metal tube model height is H_cylinder, and particle barycenter and z axle base are R_xy, limit radius R _ lim that the particle of same z axle height is allowed to generate, as Fig. 4 and shown in Figure 5:

Wherein particle barycenter and z axle base are:

$R\_\mathrm{xy}=\sqrt{x^2+{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HDA00003076627100022.png,HDA00003076627100052.png"\; state="\{\{state\}\}">y</figure-callout>}}^2}$

Its midsagittal plane trapezoidal area S is:

$S=\frac{H(R\_\mathrm{upper}+R\_\mathrm{bottom})}{2}$

Its midsagittal plane trapezoidal upper area S1 is:

$\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00003076627100022.png,HDA00003076627100061.png"\; state="\{\{state\}\}">S</figure-callout>}1=\frac{(H+H\_\mathrm{cylinder}-z)(R\_\mathrm{upper}+R\_\lim )}{2}$

Its midsagittal plane trapezoidal upper area S2 is:

$\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="HDA00003076627100022.png,HDA00003076627100052.png"\; state="\{\{state\}\}">S</figure-callout>}2=\frac{(z-H\_\mathrm{cylinder})(R\_\lim +R\_\mathrm{bottom})}{2}$

Equate with S with S2 area sum according to S1:

S=S1+S2

Can derive R_lim:

$R\_\lim =\frac{(z-H\_\mathrm{cylinder})*(R\_\mathrm{upper}-R\_\mathrm{bottom})}{H}+R\_\mathrm{bottom}$

If generating particle coordinate and radius satisfies:

R_xy+r≤R_lim

-R_upper≤x≤R_upper

-R_upper≤y≤R_upper

H_cylinder≤z≤H+H_cylinder

Accept, judge that namely this particle allows to generate.

If generate any one that particle coordinate and radius do not satisfy above-mentioned condition, refusal, judge that namely this particle does not allow to generate.

The reinforced model of pharmacy particle as shown in Figure 6.

3), the foundation of pharmacy particle model

Set up linear contact stiffness model realization to the simulation of pharmacy particle model, as shown in Figure 7.Realize between particle-particle, the interaction between particle-body of wall.

Represent with spring and damper the elasticity and the stiff character that contact between the unit in Fig. 7.Elasticity between the particle of spring representative unit, damper represent non-resilient between particulate units, use the slide block with friction factor to represent to exist between particle friction.K in figure _nb1, K _nb2Represent particle normal stiffness coefficient, K _nwRepresent body of wall normal stiffness coefficient; K _sb1, K _sb2Represent particle shear stiffness coefficient, K _swRepresent body of wall shear stiffness coefficient; F represents the friction factor of particle, body of wall; C represents spring damping, and spring damping can make spring vibration stop, and does not need special setting in discrete element emulation.

In linear contact stiffness model, suppose the rigidity series connection effect of two contact particles or particle-body of wall, so the normal stiffness COEFFICIENT K _nbb, K _nbwWith tangential contact stiffness K _sbb, K _sbwBe calculated as:

$K_{\mathrm{nbb}}=\frac{{\mathrm{<figure-callout\; id="1"\; label="K\; nb"\; filenames="HDA00003076627100022.png,HDA00003076627100061.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{nb}}*K_{\mathrm{nb}2}}{{\mathrm{<figure-callout\; id="1"\; label="K\; nb"\; filenames="HDA00003076627100022.png,HDA00003076627100061.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{nb}}+{\mathrm{<figure-callout\; id="2"\; label="K\; nb"\; filenames="HDA00003076627100022.png,HDA00003076627100052.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{nb}}}$

$K_{\mathrm{sbb}}=\frac{{\mathrm{<figure-callout\; id="1"\; label="K\; sb"\; filenames="HDA00003076627100022.png,HDA00003076627100061.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{sb}}*K_{\mathrm{sb}2}}{{\mathrm{<figure-callout\; id="1"\; label="K\; sb"\; filenames="HDA00003076627100022.png,HDA00003076627100061.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{sb}}+{\mathrm{<figure-callout\; id="2"\; label="K\; sb"\; filenames="HDA00003076627100022.png,HDA00003076627100052.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{sb}}}$

$K_{\mathrm{nbw}}=\frac{{\mathrm{<figure-callout\; id="1"\; label="K\; nb"\; filenames="HDA00003076627100022.png,HDA00003076627100061.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{nb}}*K_{\mathrm{<figure-callout\; id="1"\; label="nw\; K\; nb"\; filenames="HDA00003076627100022.png,HDA00003076627100061.png"\; state="\{\{state\}\}">nw</figure-callout>}}}{K_{\mathrm{nb}}}$

$K_{\mathrm{sbw}}=\frac{{\mathrm{<figure-callout\; id="1"\; label="K\; sb"\; filenames="HDA00003076627100022.png,HDA00003076627100061.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{sb}}*K_{\mathrm{<figure-callout\; id="1"\; label="sw\; K\; sb"\; filenames="HDA00003076627100022.png,HDA00003076627100061.png"\; state="\{\{state\}\}">sw</figure-callout>}}}{K_{\mathrm{sb}}}$

Make firmly-displacement Indentation Law can calculate the contact force of two Interaction between particles:

$F_n^c=K_n{U}_{n}n$

In formula,

Be the normal direction contact force; K _nBe the normal stiffness coefficient; U _nBe the normal direction contact displacement; N is unit normal vector.

Tangential contact force is calculated with the form of increment.When contact forms, total tangential contact force is initialized as zero, then each relative tangential displacement increment can produce the tangential contact force increment of elasticity, the tangential contact force that exists when when new tangential contact force equals current, the step begins and tangential elastic connecting touch increment sum, namely

$\mathrm{\&Delta;}{F}_s^c=k_s\mathrm{\&Delta;}{U}_s$

$F_s^c=F_{\mathrm{os}}^c+\mathrm{\&Delta;}{F}_s^c$

In formula, K _sBe tangential contact stiffness; △ U _sBe relative tangential displacement increment;

Be tangential contact force increment;

Tangential contact force for current time step;

Go on foot tangential contact force when last.

The suffered F that makes a concerted effort of particle is:

$F=F_n^c+F_s^c+\mathrm{mg}$

Can use Newton second law to set up the equation of motion according to the situation of making a concerted effort of particle:

F=ma

According to the production technology of tamping unit, pharmacy particle each time generates and just in time is metal tube permission spatial altitude, and the pharmacy particle model as shown in Figure 8.

4), slender type metal tube compacting action simulation is set up

The problem of modelling of compacting action is divided into two stages: the freely falling body after 1. pharmacy particle promotes; 2. identify bottom pharmacy particle layer, and it is applied the compacting acting force.The simulation of realization to slender type metal tube compacting action.

It tamps action frequency, freely falling body height, compacting power is all adjustable.

5), use the discrete element model of setting up

Use the discrete element model set up and carry out emulation, simulation process is divided into two stages: 1. initial balance process; 2. the equilibrium process after the compacting action is completed.In simulation process, by the computation cycles process in Fig. 9, the motion process of the inner pharmacy particle of observable.

The size of factor of porosity can embody the compaction rate of pharmacy particle, so the parameter index of pharmacy particle even density degree after selecting factor of porosity to complete as measurement compacting action.In simulation process in order to reflect the homogeneity of inner each height pharmacy particle compacted density of cylinder wall, place 6 in 6 height and measure ball, and choose two of bottoms and measure ball as the basis of carrying out the research of variable element compacting effect, tamp number of times and tamp and highly carry out the difference simulation by change, obtain tamping number of times and compacting highly to the impact effect of the inner pharmacy particle density of slender type metal tube, determine best compacting number of times, and determine optimum height on the basis of the best compacting number of times.

Factor of porosity refers in pharmacy particle, the ratio of volume of voids and whole prose style free from parallelism volume, as

$n=\frac{V_0}{V_0+V_l}$

In following formula: n---factor of porosity; V ₀---volume of voids, unit is: m ³V _l---prose style free from parallelism volume, unit are m ³

After repeatedly reinforced compacting is completed, model as shown in figure 10.Measure ball factor of porosity change curve as shown in figure 11 for 4, wherein respectively highly measuring the ball porosity curve marks respectively 1,2,3,4 for 0.05m, 0.13m, 0.21m, 0.28m.Best compacting number of times is determined curve as shown in figure 12, and curve such as Figure 13, Figure 14, shown in Figure 15 are highly determined in best compacting.

Embodiment one:

Step 1: the foundation of slender type metal tube model

Set up the hollow form cylindrical wall and simulate in the face of the slender type metal tube, the cylindrical metope of the effective side sensing of cylindrical metope is set inner, this metope id=1; Set up the bottom metope bottom cylindrical metope plug is simulated, effective side of bottom metope is set up, this metope id=2; The slender type metal tube is yielding, so its rigidity magnitude setting level is low than the ground infinitepiston.Slender type metal tube model as shown in Figure 3, its design parameter is as follows:

Cylindrical metope height is H_cylinder=0.5m;

Cylindrical metope bottom surface radius is rad=0.05m;

Step 2: the foundation of the reinforced model of pharmacy particle

Set up the funnel-form metope the reinforced model of pharmacy particle is simulated, its effective side sensing funnel-form metope is set inner, this metope id=3; Pharmacy particle feeds in raw material model as shown in Figure 6, and its design parameter is as follows:

Funnel-form metope H=0.2m

The upper opening radius is R_upper=0.1m

The lower openings radius is R_bottom=0.04m

The limit radius R_lim=0.3* (z-0.5)+0.04 of the particle that be allowed to generate of particle (x, y, z) on z axle sustained height; So the boundary condition that particle generates is following formula:

R_xy+r≤0.3*(z-0.5)+0.04

-0.1≤x≤0.1

-0.1≤y≤0.1

0.5≤z≤0.7

Particle generates in the reinforced model scope of above-mentioned pharmacy particle, completes altogether repeatedly reinforced action.

Step 3: the foundation of pharmacy particle model

Set up linear contact stiffness model the pharmacy particle model is simulated, the particle attribute that repeatedly generates is identical, pharmacy particle model initial density and actual loose shape pharmacy particle density is set approaching, and satisfies the boundary condition in step 2, increases progressively successively for its No. id.The pharmacy particle model as shown in Figure 8, its attribute design parameter is as follows:

Pharmacy particle model radius is r=0.004m;

Pharmacy particle model initial density is dens=500kg/m ³

Step 4: slender type metal tube compacting action simulation is set up

The problem of modelling of compacting action is divided into two stages: the freely falling body after 1. pharmacy particle promotes, realize by the initial velocity to the certain step number of pharmacy particle model of cylinder wall inside; 2. identify bottom pharmacy particle layer, radius r=0.004m due to the generation granular model, so judgement granular model barycenter is the particle swarm that contacts the bottom surface infinitepiston at the z direction of principal axis in 0≤z≤0.008 scope, naming this particle swarm is z_bottom, and it is applied the compacting acting force.But after completing once compacting action, due to the motion of particle, need this particle swarm of deletion at every turn, when moving, compacting redefines particle swarm until next time, if untimely deletion, this particle swarm quantity can increase along with the increase of compacting number of times, and the compacting power of Anomalies Caused is transmitted.The common simulation that realizes slender type metal tube compacting action of these two processes.

It tamps action frequency, freely falling body height, compacting power is all adjustable.

Step 5: use the discrete element model of setting up

Use the discrete element model set up and carry out emulation, simulation process is divided into two stages: 1. initial balance process; 2. the equilibrium process after the compacting action is completed.In simulation process, the motion process of the inner pharmacy particle of observable, after repeatedly reinforced compacting is completed, granular model is as shown in figure 10.4 differing heights are placed 4 and are measured ball, and its z direction of principal axis height is respectively 0.05m, 0.13m, 0.21m, 0.28m, and the measurement radius of a ball is 0.04m, and each highly measures ball id=1～4, and porosity curve marks respectively 1,2,3,4.Select bottom 0.05m, two of 0.13m to measure the basis that ball carries out the research of variable element compacting effect, tamp number of times and tamp and highly carry out the difference simulation by change, obtain tamping number of times and compacting highly to the impact effect of the inner pharmacy particle density of slender type metal tube, determine best compacting number of times, and determine optimum height on the basis of the best compacting number of times.

4 homogeneitys of measuring the inner differing heights pharmacy particle of ball factor of porosity reflection cylinder wall compacted density, as shown in figure 11.

Due to institute's adding medicine particle action of gravitation, bottom pharmacy particle factor of porosity is further reduced after each reinforced completing; Once compacting action of the most advanced and sophisticated expression of each curve, as seen from the figure, after each compacting action was completed, the pharmacy particle factor of porosity all reduced, and namely pharmacy particle density increases, and shows that the compacting action can make pharmacy particle density raise; The measurement ball factor of porosity that the measurement ball factor of porosity that z direction of principal axis height is higher is lower than z direction of principal axis height is large, shows that the pharmacy particle compacted density successively decreases from bottom to top successively.The factor of porosity data that derive after reinforced compacting is completed are as shown in table 1:

Factor of porosity tables of data after the reinforced compacting of table 1 is completed

Measure the ball height	0.05m	0.13m	0.21m	0.28m
					Factor of porosity	0.318	0.336	0.341	0.347

Wherein z direction of principal axis height is that the factor of porosity average of 0.05m, 0.13m, 0.21m, 0.28m is 0.3355, variance is 0.0001175, variance is less, showing reinforced compacting complete after z direction of principal axis height be that the factor of porosity of 0.05m, 0.13m, 0.21m, 0.28m is more even, namely each z direction of principal axis height pharmacy particle density is comparatively even.

1, best compacting number of times is determined

Observe by experiment, analyze, tamp highly too low compacting technique without positive effect, therefore, first fixing compacting is highly 200mm, and increasing the compacting number of times is 10 times, starts the balanced recycle of simulation; Monitoring pharmacy particle bottom 0.05m measures ball factor of porosity change curve as shown in figure 12.

Measure ball factor of porosity tables of data No. 1 after ten compacting processing simulations of table 2

The compacting number of times	The factor of porosity of pharmacy particle after stable
		The incipient stability state	0.4258

For the first time	0.3804
		For the second time	0.3627
For the third time	0.3363
		The 4th time	0.3141
The 5th time	0.3006
		The 6th time	0.2907
The 7th time	0.2892
		The 8th time	0.2871
The 9th time	0.2831
		The tenth time	0.2809

Simulate the factor of porosity data of rear pharmacy particles in conjunction with the factor of porosity change curve of Figure 12 and ten compactings of table 2, front 6 compacting simulations can reduce the factor of porosity of pharmacy particle by a relatively large margin, therefore, front 6 compacting simulations can improve the density of powder granule in metal tube faster; Rear 4 compacting simulations without too large effect, namely can not increase the density of powder granule in metal tube for the factor of porosity that reduces pharmacy particle greatly.So must satisfy high-level efficiency and tamp in compacting technique is highly under the prerequisite of 200mm, best compacting number of times is 6 left and right.

Under the prerequisite of the best compacting number of times 6 times, change the compacting height, the impact of the variation of simplation verification compacting height on powder granule density in the slender type metal tube:

2, best compacting is highly definite

Increasing compacting is highly 250mm, simulates six times compacting technique, pharmacy particle in the slender type metal tube is measured the ball factor of porosity for No. 1, No. 2 carry out record, and the factor of porosity change curve as shown in figure 13.

Compacting height 250mm, in six compacting processing simulation processes, two measurement ball Chinese medicine particle porosity delta datas are as shown in table 3.

Table 3 compacting height 250mm pharmacy particle factor of porosity delta data

Factor of porosity data according to pharmacy particle after six compacting simulations of Figure 13 factor of porosity change curve and table 3, the factor of porosity change curve that ball is measured in wherein measure ball No. 1 and No. 2 marks respectively 1,2, when compacting highly is 250mm, measuring the ball factor of porosity for two is more or less the same, factor of porosity maximal phase difference is 0.0335, and the average pore difference is 0.022683.Therefore, when compacting highly was 250mm, in the slender type metal tube, the homogeneity of powder granule accumulation system density was better.

Increasing compacting is highly 300mm, simulate six times compacting technique, pharmacy particle in the slender type metal tube No. 1, No. 2 is measured the ball factor of porosity carries out record, the factor of porosity change curve as shown in figure 14, the factor of porosity change curve of wherein measuring ball and measure for No. 1 and No. 2 ball marks respectively 1,2.

Compacting height 300mm, in six compacting processing simulation processes, two measurement ball Chinese medicine particle porosity delta datas are as shown in table 4.

Table 4 compacting height 300mm pharmacy particle factor of porosity delta data

When compacting highly is 300mm, highly the differences for two measurement ball factor of porosity of 250mm are large than compacting can to see from Figure 14 and table 4 mesoporosity degree delta data the porosity difference of measuring balls for No. 1, No. 2, therefore, the increase of compacting height can make the homogeneity of powder granule density in the slender type metal tube reduce, when compacting highly is 300mm, two are measured ball factor of porosity maximum difference is 0.0523, and the average pore difference is 0.031867; The homogeneity angle of powder granule density is considered in the slender type metal tube, and compacting is highly unsuitable excessive.

Increasing compacting is highly 350mm, simulate six times compacting technique, pharmacy particle in the slender type metal tube No. 1, No. 2 is measured the ball factor of porosity carries out record, the factor of porosity change curve as shown in figure 15, the factor of porosity change curve of wherein measuring ball and measure for No. 1 and No. 2 ball marks respectively 1,2.

Compacting height 350mm, in six compacting processing simulation processes, two measurement ball Chinese medicine particle porosity delta datas are as shown in table 5.

Table 5 compacting height 350mm pharmacy particle factor of porosity delta data

Measure factor of porosity change curve and the table 5 mesoporosity degrees of data of balls two of Figure 15, in the time of can finding out compacting highly for 350mm, measure the porosity difference of ball for No. 1, No. 2 apart from larger, the maximum porosity difference reaches 0.0921, the average pore difference is 0.071283, at this moment, in the slender type metal tube, the pharmacy particle bottom is larger with the top porosity difference, has not satisfied the requirement of powder granule density uniformity in the slender type metal tube.

At 3 groups, 250mm, 300mm and 350mm, in compacting compacting simulation highly, the efficient requirement of powder granule compacting in comprehensive slender type metal tube and the requirement of density uniformity, compacting is highly unsuitable too high, and the best compacting of simulation is highly 300mm.

Explanation is at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although with reference to preferred embodiment, the present invention is had been described in detail, those of ordinary skill in the art is to be understood that, can modify or be equal to replacement technical scheme of the present invention, and not breaking away from aim and the scope of the technical program, it all should be encompassed in the middle of claim scope of the present invention.

Claims (5)

1. the discrete element analytical approach of a slender type metal tube medicament compacting state, is characterized in that, the concrete analysis step is as follows:

1) set up slender type metal tube model, adopt the hollow form cylindrical wall to simulate in the face of the slender type metal tube, the effective side of column type metope is cylindrical metope inwall, sets up the bottom metope bottom cylindrical metope plug is simulated, and the limited side of bottom metope is set up;

2) set up the reinforced model of pharmacy particle, adopt the funnel-form metope that the reinforced model of pharmacy particle is simulated, its effective side is funnel-form metope inwall, and sets the boundary condition that it generates for pharmacy particle;

3) according to step 2) in the pharmacy particle that obtains generate boundary condition, setting up linear contact stiffness model simulates the pharmacy particle model, generate several times particle, each particle attribute that generates is identical, pharmacy particle model initial density and actual loose shape pharmacy particle density is set approaches;

4) carry out slender type metal tube compacting action simulation;

5) utilize the discrete element model that step 1) to step 4) is set up to tamp emulation, particle porosity when observing inner pharmacy particle motion and differing heights in simulation process, and adopt factor of porosity as the parameter index of pharmacy particle even density degree after weighing the compacting action and completing, inner each height pharmacy particle density uniformity of slender type metal tube after the checking compacting is completed, thus determine best compacting number of times and best compacting height.

2. the discrete element analytical approach of a kind of slender type metal tube medicament compacting state as claimed in claim 1, is characterized in that step 2) the boundary condition judgment formula that generates of Chinese medicine particle is:

R_xy+r≤R_lim

-R_upper≤x≤R_upper

-R_upper≤y≤R_upper

H_cylinder≤z≤H+H_cylinder

Wherein, generating the particle center-of-mass coordinate is (x, y, z), particle radius is r, the reinforced model height of pharmacy particle is H, the upper opening radius is R_upper, and the lower openings radius is R_bottom, and slender type metal tube model height is H_cylinder, particle barycenter and z axle base are R_xy, limit radius R _ lim that the particle of same z axle height is allowed to generate.

3. the discrete element analytical approach of a kind of slender type metal tube medicament compacting state as claimed in claim 1, is characterized in that, sets up linear contact stiffness model described in step 3) to the concrete grammar of pharmacy particle model to be:

Make the contact force that firmly can calculate two Interaction between particles with the displacement Indentation Law:

$F_n^c=K_n{U}_{n}n$

In formula,

Be the normal direction contact force; K _nBe the normal stiffness coefficient; U _nBe the normal direction contact displacement; N is unit normal vector;

$\mathrm{\&Delta;}{F}_s^c=k_s\mathrm{\&Delta;}{U}_s$

$F_s^c=F_{\mathrm{os}}^c+\mathrm{\&Delta;}{F}_s^c$

In formula, K _sBe tangential contact stiffness; △ U _sBe relative tangential displacement increment;

Be tangential contact force increment;

Tangential contact force for current time step;

Go on foot tangential contact force when last, so the suffered F that makes a concerted effort of particle is:

$F=F_n^c+F_s^c$

Can use Newton second law to set up the equation of motion according to the situation of making a concerted effort of particle:

F=ma。

4. the discrete element analytical approach of a kind of slender type metal tube medicament compacting state as claimed in claim 1, is characterized in that, the metal tube of slender type described in step 4) compacting action simulation includes two stages:

4-1) the freely falling body stage of pharmacy particle;

4-2) pharmacy particle bottom compacting acting force applies;

Described compacting action can be identified bottom pharmacy particle layer, and compacting action frequency, freely falling body height and compacting power are all adjustable.

5. the discrete element analytical approach of a kind of slender type metal tube medicament compacting state as claimed in claim 1, is characterized in that, tamps emulation and observation in step 5) and include two stages:

5-1) initial equilibrium conditions emulation and observation, initial equilibrium conditions is initial equilibrium state after reinforced;

Balance emulation and observation after 5-2) the compacting action is completed.

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