JP3345662B2 - Simulation method and apparatus for plastic working experiment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD The present invention relates to press working and forging.
Machining process or mold in plastic working such as machining
Obtain and evaluate basic data such as design or processing defect countermeasures
・ Simulation of plastic working experiment for the purpose of study
The present invention relates to an installation method and an apparatus.

[0002]

2. Description of the Related Art Conventionally, machining process design by plastic working
The evaluation and examination of the mold design are conducted as follows.
You.(1) Evaluation and examination based on actual product processing results  Select processing materials and processing equipment for the designed product.
And design the machining process. Next, the processing process
Perform the mold design according to. Then, the appropriateness of the machining process
Mold to understand the fluidity and flowability of the processing material in the mold.
From the results of trial production and actual processing of the product,
Judgment was made. However, with this method,
The judgment of rejection is often based on the past experience and intuition of a skilled technician.
Numerically to objectively judge where to improve
Data could not be obtained. In addition, it takes time and effort to prototype molds.
If a negative decision is made because of the time required, try again.
Making it took a lot of time and effort. And skilled
Optimized results after technician trial and error
However, the process could not be systematized.

[0003](2) Evaluation and examination by computer simulation  Computer simulation using numerical mechanics in the finite element method.
Flow analysis and strain distribution analysis of the processed material.
Therefore, there is a method of evaluating and examining the design. But this
In the method, the contact conditions with the mold before and after processing, friction conditions,
Assuming that boundary conditions, material deformation characteristics, etc. are constant
Are changing from time to time, and the material is deformed.
Not only can not accurately simulate the state
Results can be very different from elephants,
I was missing. In addition, setting of numerical calculation models and practical methods
It takes considerable skill and time to create a
Tens of thousands of hundreds of thousands of days
In some cases. In addition, complete mistakes in setting conditions
It is also difficult to eliminate the
The analysis program had to be modified. Also,
Even if you try to analyze only the part of the material you want to consider,
In the analysis by the element method, numerical calculations are performed in relation to the whole
Therefore, the calculation time was not reduced.

[0004]

SUMMARY OF THE INVENTION The present inventionIs more than conventional
It was made in view of problems in technology,Next
Una plastic working experiment simulationProvide method and apparatus
The purpose is to do.  (1) No need for a numerical calculation model
Process design and mold without the need for advanced skills
Change key design considerations arbitrarily and extensively
Can be analyzed. (2) Contact condition with the mold, friction condition, boundary condition, material
The state in which the material is deformed by changing from moment to moment, such as deformation characteristics
Can be analyzed at each stage, and the analysis results in line with the actual phenomena
ToProfitCan be. (3) Analyze only the part of the material you want to study
Results similar to those analyzed physicallyToObtainable.

[0005]

Means for Solving the Problems According to the invention of the present application, which is provided to solve the above-mentioned problems, in a method of simulating plastic working experiments, a material having a predetermined shape is placed on a plane including its central axis.
And halves it into a model material.
Draw a grid line on the plane containing the central axis of one model material.
A step of writing grid points by, and a step of plastically processing the model material step by step, measuring the processing time, and a step of measuring the displacement of each grid point after the processing of each step of the plastic processing, numerical analysis binding consisting of equivalent strain and the corresponding strain rate and strain rate components and the plastic flow velocity component for each grid point of each plastic working step by numerical analysis based on the processing time measurement data and displacement measurement data of the grid point
And obtaining a result, the model material based on the numerical results
It was decided whether <br/> Ranaru the step of determining acceptability with respect to the shape and internal properties. This makes it possible to grasp the state of deformation at that point from the actual overall processing result at each processing stage and the numerical analysis result at an arbitrary point in the model material at that stage. In addition, since each point is analyzed independently, it is only necessary to analyze the part of the material that you want to study,
It is possible to obtain the same result as in the case of analyzing the whole.

In the step of measuring the displacement of the lattice point after the completion of each step of the plastic working ,
Measure the displacement of the lattice point of the part to be examined on the plane including the central axis and numerically analyze it.Each plastic working stage has a plastic flow rate component, a strain rate component, and an equivalent strain rate corresponding to the lattice point of the measured part at the measurement point. A numerical analysis result consisting of strain can also be obtained.

[0007] The invention of the present application, which is provided to solve the above-mentioned problems, is provided in a plastic working experiment simulation apparatus,
Material of a specific shape is divided in half by the plane containing its central axis
And at least one of the central axes divided in half
Press machine for stepwise plastic working of a model material with grid points marked by grid lines on the surface including the surface, time measuring device for measuring the time of plastic working for each plastic working stage, and model material for each plastic working stage A grid point coordinate reading device that measures the shape and the coordinates of the grid points, and the coordinate data of the grid points read by the grid point coordinate reading device and the processing time measured by the time measuring device for each plastic working step An arithmetic processing unit that stores a numerical analysis program that obtains a numerical analysis result consisting of a plastic flow velocity component, a strain velocity component, an equivalent strain rate, and an equivalent strain at each grid point in each plastic working stage by performing arithmetic processing based on data. And characterized by the following. This makes it possible to grasp the state of deformation at that point from the actual overall processing result at each processing stage and the numerical analysis result at an arbitrary point in the model material at that stage. Also, since each point is analyzed independently,
By analyzing only the portion of the material that is desired to be studied, the same result as in the case of analyzing the entire material can be obtained. The plastic working device is, for example, a hydraulic press, and the grid point coordinate reading device is a scanner, a digitizer, or the like.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a plastic working experiment simulation method according to the present invention will be described. The design of the working process by the plastic working experiment simulation method according to the present invention is performed by the steps shown in FIGS. Determine the material shape and produce the material. On the observation surface of the material, the intersection (grid
Point) . Design and manufacture molds. The material is processed in stages (sequential processing), and the intersections (grid points) of the distorted grid lines of the material are measured at each stage.
Unsteady deformation analysis is performed from displacement data of grid points,
Calculate the plastic flow rate component, strain rate component, equivalent strain rate, and equivalent strain at each stage of the deformation process.
The quality of the target shape and the internal characteristics is determined. If the judgment is good, the design is completed. In the case of a negative determination, one of the following steps is performed, and this is repeated until a good determination is made. Change the processing conditions referring to the analysis result of and return to. Change the mold shape with reference to the analysis result of and return to. The material shape is changed with reference to the analysis result of and the process returns to.

By the above-mentioned method , even in the processing with the friction distribution or the material internal temperature distribution that changes every moment, the analysis is performed from the displacement data of the lattice points affected by the distribution, so that actual phenomena are not obtained. Analysis can be performed according to it, and high reliability can be expected. In an experimental simulation using a real metal material as a material, it is possible to confirm a deformed shape and grasp an internal structure at any stage during processing. As described above, according to the plastic working experiment simulation method according to the present invention, data and numerical analysis for each stage can be interactively and semi-automatically performed, and the tool shape, lubrication conditions, working materials, etc. A simulation in which the examination items are changed arbitrarily and widely can be easily performed.

Next, a plastic working experiment simulation apparatus according to the present invention will be described with reference to FIG. The plastic working experiment simulation apparatus 8 according to the present invention includes: (a) a press 11, a press sensor unit 12 such as a load meter and a displacement meter, a ram 13, a punch 14,
Press mechanism 1 including a die 15 on which the press 6 is disposed
(B) a measuring unit 2 for recording and displaying the voltage change from the press sensor unit 12; and (c) controlling the measuring unit 2 to quantitatively reproduce the press characteristics.
A central processing unit 3 of a computer that edits and manages and executes a series of procedures; and (d) coordinates of grid points (intersections of grid lines 17) in an XY orthogonal coordinate system and an r, θ, z coordinate system. (E) kneading a reading device unit 4 such as a scanner or a digitizer, and (e) a numerical analysis program 5 for controlling the reading device unit 4 and performing unsteady deformation analysis from each coordinate value of a grid point, and (f) plasticine.・ Vacuum kneading machine 18 for deaeration
And (g) a thermostat 19 for conditioning plasticin.

Although the working simulation using the actual metal material can be performed by using the plastic working experiment simulation apparatus 8 according to the present invention, at the stage of designing the mold, it is necessary to use a plasticine which models the actual metal material. Thereby, the material shape can be easily examined.

Here, a flowchart of a numerical analysis program for performing an unsteady deformation analysis will be described with reference to FIG.
The moving distance of the lattice point (observation lattice point) on the distorted lattice line obtained by the sequential deformation is differentiated by time (by difference calculation), and the plastic flow velocity components (U, V) of the lattice point are calculated. Fig. 5 (b) to perform strain analysis
The square grid lines (square grid lines for calculation) shown in FIG.
It is placed on the observation grid point shown in (a). One of (A) a rectangular coordinate system and (B) a cylindrical coordinate system shown in FIG. 4 is selected. , 'Strain rate components grid point calculation square lattice line (calculation lattice point) (εx, ε y, γxy ) or (εr, εθ, εz, γrz ) is calculated. ,
′ Calculate the equivalent strain rate εv of the grid point for calculation.
The equivalent strain rate value of the observation grid point is obtained from the equivalent strain rate value of the calculation grid point. The equivalent strain ε is calculated by integral calculation using the relationship between the equivalent strain rate value of each observation grid point and time.

Here, the calculation method in the 'step is
explain about. First, the calculation positive shown in FIG.
The plastic flow velocity component value at the grid point (for example, point P) is calculated as
The known plastic flow velocity component of the observation grid point closest to P
Using the minute values, calculation is performed in accordance with the following procedures a to c. a. Using the inequality shown in FIG.
The child points are divided into quadrants I to IV. b. The observation grid point closest to the point P for each quadrant
Find out. c. Known plastic flow velocity on four observation grid points surrounding point P
Plasticity at point P by four-point linear interpolation calculation from degree component value
Flow velocity component value (plastic flow velocity component value at grid point for calculation
(U, V)). In the corner, the same calculation procedure is used.
Plastic flow velocity at observation grid points belonging to the three quadrants
Using the degree component value, a three-point linear interpolation
The value of the plastic flow velocity component in the test. Next calculation
Using the plastic flow velocity component value at the grid point
Calculate the strain rate component value of the grid point for calculation. Stage;
The strain rate component value of the grid point for calculation in the Cartesian coordinate system
Ask. εx = ∂U / ∂X εy = ∂V / ∂Y γxy = ∂V / ∂X + ∂U / ∂Y where ｘx is the strain rate component in the X direction, and ｙy is the strain rate component in the Y direction.
Γxy is the shear strain rate component
It is. 'Step; strain rate of grid point for calculation in cylindrical coordinate system
Find the degree component value. εr = ∂U / ∂r εθ = U / r εz = ∂V / ∂Z γrz = ∂U / ∂Z + ∂V / ∂r where εr is the strain rate component in the r direction and εθ is the θ direction.
The strain rate component, εz, is the strain rate component in the Z direction.
Γrz is the shear strain rate component.

[0014]Next, the calculation formula in the 'step is as follows.
Shown in Step: Equivalent strain of grid point for calculation in rectangular coordinate system
Is the strain rate component at the calculated grid point
Is obtained from the following equation. εv = 2/3 (3εx ² + 3 / 4γxy ² ) ^1/2 (However, εx + εy = 0.) 'Step; equivalent strain rate of grid point for calculation in cylindrical coordinate system
εv 'is the strain rate component at the computational grid point in the'
It can be obtained from the following equation. εv ′ = ｛2/3 (εr ² + Εθ ² + Εz ² + 1 / 2γrz ² )｝ ^1/2 (However, εr + εθ + εz = 0) In the subsequent step,
The equivalent strain rate value (εv (or εv
v ′)), the equivalent strain rate εV of the target observation grid point
(Or εV ′). The last step
The formula for calculating the equivalent strain ε of the observation grid point is
is there. In the case of a rectangular coordinate system; ε = ∫εVdt In the case of a cylindrical coordinate system; ε = ∫εV′dt

Embodiment 1 As an embodiment of the plastic working simulation method according to the present invention, a working process of a bolt having a decorative head was studied. An object to be processed is a head portion 22 of the bolt 21 shown in FIG. 6, and the head portion 22 has a flange portion 22a which is an undercut. The simulation was performed with 2 bolts 21 made of white plasticine.
The test was performed with the model material 23 times. The production of the model material 23 was performed according to the following procedures. After kneading and degassing the plasticine with the vacuum kneading machine 18 shown in FIG. 2, the plasticine is extruded with a stepped mold to form the model material 23. In order to stabilize mechanical properties, it is kept in a thermostat 19 at 20 ° C. for 20 hours or more. The model material 23 is divided in half by a plane including the central axis, and grid lines are imprinted on one surface at equal intervals.

[0016] The die 15 shown the model material 23 in FIG. 8
And processed by a punch 14 of a hydraulic press having a maximum load of 29 KN. The processing was performed in four stages up to the reduction rate Rh = 34% of the height H of the model material 23 shown in FIG. 7 at a temperature of 21 ° C. (room temperature) and a pressing speed of 32 mm / s. The contact surface between the die 15 and the model material 23 was polished with sandpaper. Further, yellow petrolatum as a lubricant was thinly and uniformly applied to the die 15 side. The grid point coordinates at each stage of deformation were captured by a digitizer and numerical analysis was performed.

FIG. 9 shows an analysis result obtained by the simulation. The four stages of the deformation shown in FIG. 9 (Rh = 0%, 11
%, 23%, and 34%), the plastic flow velocity distribution, the equivalent strain rate distribution, and the equivalent strain distribution are examined. In addition, only the half axis is shown except for the symmetry of the shape. Outer shape From the outer shape, the molding deforms into a barrel shape from the top of the head, gradually forming a lower flange, and in the final stage, after the flange is filled, extrusion forward and material flow simultaneously occur simultaneously Can be confirmed. Plastic flow velocity distribution Observation of the plastic flow in the formation of the flange shows that, in the final stage, the plastic flow near the flange is divided in the forward extrusion direction and the circumferential direction of the flange. Further, it can be seen that a dead metal zone is formed at the branch point. The equivalent strain rate distribution shows that the equivalent strain rate distribution has a high value in the flange portion throughout each deformation stage, and in the final stage, the extruded shaft portion has a particularly high value due to the flow of the material by forward extrusion. In the final stage, the plastic deformation region of ε ≧ 4.0 extends downward from a line crossing obliquely upward from the flange portion to the central axis. This can be said to be a characteristic of the equivalent strain rate distribution that appeared in response to the plastic flow. Equivalent strain distribution In the equivalent strain distribution, a large plastic strain occurs at the center of the material at the beginning of the deformation stage, and the value increases as the deformation progresses.

According to the plastic working experiment simulation apparatus of the present invention, it is also possible to take out and analyze only a portion to be examined. That is, it is possible to input and analyze the grid point coordinates of only a part having a problem, for example, a part involved, such as a damaged part of a mold or a part where a material defect occurs, in the obtained lattice pattern. This is because there is no need to set a mathematical model of the boundary conditions between the study area and the other areas. Therefore, the calculation time is shortened, and a quick machining process can be studied. (Example 2) Only the flange portion of the head portion 22 of the bolt 21 studied in Example 1 was simulated. Its resulting lattice pattern in FIG. 10 (B), the equivalent strain distribution in the final step shown in FIG. 10 (C). Also, for comparison, Example 1 was used.
FIG. 10 (A) shows the equivalent strain distribution at the final stage of the overall analysis result obtained in. Now, the equivalent strain distribution in the part analysis shown in FIG. 10 (C), the equivalent strain distribution in that part of the overall analysis, shown in FIG. 10 (A), it is confirmed that almost the same results. It is considered that the analysis results are slightly different due to a difference calculation error in the peripheral portion of the analysis region in the partial analysis and an analysis error due to a small number of observation grid points.

[0019]

According to the present invention, there are the following excellent effects. (1) Numerical calculation models are not required, and the main study items in machining process design and die design can be analyzed arbitrarily and widely, without requiring skill such as past experience and intuition. (2) The state in which the material is deformed by changing every moment, such as the contact condition with the mold, the friction condition, the boundary condition, and the deformation characteristics of the material, can be analyzed at each stage, and the analysis results based on actual phenomena
The resulting can Rukoto. (3) only just the analyzing portion to be examined of the material, it is possible to obtain the same results as in the case of totally analyzed.

[Brief description of the drawings]

FIG. 1 is a functional explanatory view of a plastic working experiment simulation apparatus according to the present invention.

FIG. 2 is an explanatory view of a plastic working experiment simulation apparatus according to the present invention.

FIG. 3 is a flowchart of a numerical analysis program according to the present invention.

FIG. 4 is an explanatory diagram of a numerical analysis program according to the present invention.

FIG. 5 is an explanatory diagram of a numerical analysis program according to the present invention.

FIG. 6 is an explanatory view of Embodiment 1 of a plastic working experiment simulation apparatus according to the present invention.

FIG. 7 is an explanatory view of Embodiment 1 of a plastic working experiment simulation apparatus according to the present invention.

FIG. 8 is an explanatory view of Embodiment 1 of a plastic working experiment simulation apparatus according to the present invention.

FIG. 9 is an explanatory view of Embodiment 1 of the plastic working experiment simulation apparatus according to the present invention.

FIG. 10 is an explanatory view of a plastic working experiment simulation apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 (X, Y): Cartesian coordinate system (r, θ, z): Axisymmetric cylindrical coordinate system U, V:Observation grid pointX, Y or r, Z direction plastic
Flow velocity components εx, εy:Calculation of grid points in a rectangular coordinate systemX, Y
Direction strain rate components εr, εθ, εz:Calculation of grid points in cylindrical coordinate system
r, θ, z strain rate components γxy, γrz:Calculation of grid pointsShear strain rate component εv:Calculation of grid points in a rectangular coordinate systemEquivalent strain rate
Every timeεv ': equivalent strain of grid points for calculation in cylindrical coordinate system
speed εV: equivalent strain of the observation grid point in the rectangular coordinate system
speed εV ′: equivalent strain of observation grid point in cylindrical coordinate system
speed  ε:Observation grid pointEquivalent strain H: Height Rh: Reduction rate of height 1 Press mechanism 2 Measurement unit 3 Central processing unit 4 Reading unit 5 Numerical analysis program 8 Plastic working experiment simulation device 11 Press 12 Press sensor unit 13 Ram 14 Punch 15 Die 16 Material 17 Grid wire 18 Vacuum clay kneader 19 Incubator 21 Bolt 22 Head, 22a Flange 23 Model material

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-208978 (JP, A) JP-A-4-279238 (JP, A) JP-A-6-119418 (JP, A) JP-A-5-208 169525 (JP, A) JP-A-6-328180 (JP, A) JP-A-7-202354 (JP, A) JP-A-7-105178 (JP, A) JP-A-58-79157 (JP, A) JP-A-6-126406 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21J 1/00-13/14 B21J 17/00-19/04 B21K 1/00-31 / 00 B30B 15/00 G06F 17/00 G06F 17/50

Claims (3)

(57) [Claims] 1. A material having a predetermined shape is cut in half on a plane including its central axis.
Divided into model material, and at least one of the half divided
To draw grid lines on the plane containing the central axis of the model material
A step of noting more grid points , a step of plastically processing the model material in stages, and measuring a processing time thereof; and a step of measuring displacement of each grid point after completion of the processing in each step of the plastic processing, Numerical analysis based on displacement measurement data and machining time measurement data at grid points to obtain a numerical analysis result consisting of plastic flow velocity component, strain rate component, equivalent strain rate, and equivalent strain at each lattice point in each plastic working stage Based on the process and the numerical analysis results, the shape and internal
Plastic working experimental simulation method characterized by comprising the step of determining the acceptability with respect to part characteristics. 2. A process for measuring the displacement of the grid points after the completion of processing of the plastic working stages, said in the model material
Measure the displacement of the lattice point at the portion of the surface including the mandrel that you want to study and analyze it numerically.The plastic flow velocity component, the strain velocity component, the equivalent strain rate, and the equivalent strain at each lattice point at that measurement point in each plastic working stage 2. The plastic working experiment simulation method according to claim 1, wherein a numerical analysis result comprising: 3. A material having a specific shape is formed on a plane including its central axis.
Half-split, at least one of half-split
Grid points are marked by grid lines on the plane containing the central axis of
Grid points to be measured and a press device for plastic working stepwise model material, and time measuring device for measuring the time of plastic working by plastic working step, the model material shape as the grid points of each plastic working stage coordinates Coordinate reading device, by performing processing based on the coordinate data of the grid points read by the grid point coordinate reading device for each plastic working stage and the processing time data measured by the time measuring device, each plastic working stage Number consisting of plastic flow velocity component, strain velocity component, equivalent strain rate, and equivalent strain for each lattice point
An arithmetic processing device in which a numerical analysis program for obtaining a value analysis result is stored, and a simulation machine for plastic working experiments characterized by: