CN103894449A - Force checking disc and using method thereof - Google Patents

Abstract

The invention discloses a force checking disc and a using method of the force checking disc. The force checking disc consists of a disc of which the positive and reverse sides are provided with reverse characters. Advanced mathematical knowledge is not needed, the radial and tangential stress at any point in a deformation area of multiple plate forming processes such as drawing, hole flanging and local forming can be directly checked without calculation, the stress distribution rule in the deformation area can be rapidly determined, and the change rule of deformation force in the forming process is rapidly determined.

Description

One is looked into power dish and using method thereof

Technical field

The one the present invention relates in Plastic Forming field is looked into power dish and using method thereof.

Background technology

Studying the stamping matter of utmost importance of circular slab is exactly the stress distribution law that solves the plastically deforming area of slab, and its resolution principle is simultaneous solution stress equilibrium equation and yield criterion (also needing if desired plastic constitutive relation).In order to simplify solution procedure, in engineering, conventionally adopt " slab method ", the yield criterion that utilization is simplified and stress equilibrium equations simultaneousness are to obtain the approximate solution of stress distribution law.In view of approximate solution often can not meet the needs of furtheing investigate sheet forming problem, ask its rigorous analytic solutions by Mi Xisi (Mises) yield criterion herein.It is very complicated that its solution procedure seems at first sight, is not therefore used widely.

Summary of the invention

The object of this invention is to provide one and look into power dish, without advanced mathematical knowledge, can be not as calculated, directly find any point in the multiple plate forming process deformed areas such as drawing, hole flanging, partial plastic forming radially with tangential stress, can promptly determine the stress distribution law in deformed area, promptly determine the Changing Pattern of deformation force in forming process.

For achieving the above object, the technical scheme that the present invention takes is:

One is looked into power dish, described Charlie is coiled the disk of being put upside down mutually by a positive and negative two sides word and is formed, described disk front is the polar diagram of describing the parameter curve r=f (θ) of various forming modes, described coordinate diagram is made up of the radially relative coordinate of angle coordinate and some position, described angular coordinate theta is spent to (+180) by 0 counterclockwise, spend clockwise the radially relative coordinate of described position to (180) by 0

or

scale be all by 0 to 1, described reverse side is a pair of stress reference axis that is 60 degree obliques, represents respectively radially and the relative value of tangential stress with

coordinate scale is by 0 to ± 1.155, and described reverse side is also provided with two families respectively perpendicular to the grid lines of stress reference axis separately.

The using method of a kind of power of looking into dish as claimed in claim 1.

The present invention has following beneficial effect:

1). do not need complicated theory to calculate, even must not find the concrete numerical value of parameter angle θ, look into intersection point P and Q on power dish as long as find ₁position, can directly find arbitrfary point radially with tangential stress value.Conversely, also can look into its some position (step is contrary with above-mentioned example) on flange by given stress.

2). the some position in deformed area is with relative coordinate

or

represent, got rid of the impact of flange actual size size, therefore any moment of deformation process is all suitable for.Both can calculate the stress that certain specifies moment specified point, can determine again the stress distribution of deformed area, and be particularly suitable for the STRESS VARIATION in deformation process to carry out dynamic follow-up study.

3). stress, with relative stress value representation, has been got rid of concrete material yield stress (σ _i) impact, therefore the material of any different yield stresses is all suitable for.

4). in described disk, curve A B represents deep-drawing technique, and CD represents flange hole technology, and thick-walled sleeve when AE representative is subject to interior pressure is out of shape, and thick-walled sleeve when CF representative is subject to external pressure is out of shape, and GH represents the elongation strain under inside and outside pressure acts on simultaneously with mandrel thick-walled sleeve.

Brief description of the drawings

Fig. 1 is r=f (θ) curve positive in the present invention;

Fig. 2 is the stress coordinate plane of reverse side in the present invention;

Fig. 3 is the positive example schematic diagram of searching in one embodiment of the invention;

Fig. 4 be in one embodiment of the invention reverse side search example schematic diagram.

Detailed description of the invention

In order to make objects and advantages of the present invention clearer, below in conjunction with embodiment, the present invention is further elaborated.Should be appreciated that specific embodiment described herein, only in order to explain the present invention, is not intended to limit the present invention.

This concrete one of implementing is looked into power dish, described Charlie is coiled the disk of being put upside down mutually by a positive and negative two sides word and is formed, described disk front is the polar diagram of describing the parameter curve r=f (θ) of various forming modes, described coordinate diagram is made up of the radially relative coordinate of angle coordinate and some position, described angular coordinate theta is spent to (+180) by 0 counterclockwise, spend clockwise the radially relative coordinate of described position to (180) by 0

or

scale be all by 0 to 1, described reverse side is a pair of stress reference axis that is 60 degree obliques, represents respectively radially and the relative value of tangential stress

with

coordinate scale is by 0 to ± 1.155, and described reverse side is also provided with two families respectively perpendicular to the grid lines of stress reference axis separately.

Using method is as follows:

Embodiment 1

Now, taking the stress of looking into certain point on drawing flange as example, introduce the using method of looking into power dish.

Look into a certain any time in drawing process and (use R _trepresent), any point on flange (representing with r) radially with tangential stress.

Known: in this moment, flange outer radius is R _t=100mm.

Require: search the radial stress that radius is r=77mm place with tangential stress

value.

Operating procedure:

1, calculate relative coordinate value

2, on positive polar diagram, find relative coordinate to be

concentric circles (as Fig. 3).(the closeer location of concentric circles is more accurate)

3, look for it and the intersection point P (as Fig. 3) of " drawing curve " AB along this concentric circles

4,, from this intersection point P, look for its corresponding points Q1 (as Fig. 3) on cylindrical along radial direction.

5, be turned to reverse side.On " the stress coordinate diagram " of reverse side cylindrical (Fig. 4), find and positive some Q ₁in the some Q of same position ₂.(note: positive some Q ₁point Q with reverse side ₂the same point on strain disc outward flange in fact)

6, by a Q ₂set out, along two family's netting twines, arrive respectively

with

reference axis is looked for intersection point M and N.The scale value (0.82) that the scale value (0.3) that this M is ordered and N are ordered is exactly on drawing flange

the radial stress at=0.77 place and tangential stress

Embodiment 2

Known: the flange outer radius R in certain moment in drawing process _t.Ask: this moment contiguous die mouth r ₀the stress at place.Operating procedure: 1. measure die port radius r ₀outer radius R with this moment flange _t, calculate die mouth relative coordinate value

all the other steps are with example 1.

Embodiment 3

Known: blank radius R ₀with die port radius r ₀, ask: die mouth place initial time drawing maximum stress.Operating procedure: 1. calculate relative coordinate value

(drawing coefficient).

Step 2,3,4,5, with example 1, find initial time die mouth

the radial stress at place.

6. this stress is taken advantage of to area 2 π r ₀t, obtains deep drawing deformation force P.(if it is more accurate to require, and can on the basis of the 5th step, increase the additional stress that the factors such as flanging, friction and bending cause again).

Embodiment 4

Ask the stress distribution law of drawing ledge zone.

Operating procedure: 1. radially select series of points position ri on flange, calculate its relative coordinate value separately

find a series of concentric circles.

2. on positive drawing curve A B, find out the intersection point p of a series of concentric circles and this curve A B _i.

3. from each intersection point, radially find out a series of and intersection point p looking into power dish outer rim _icorresponding Q _1ipoint.

4. power dish is looked in upset, looks for a series of and Q to the outer rim of reverse side _1ithe Q overlapping _2ipoint.

5. by a series of Q of reverse side outer rim _2ipoint, is following in grid lines to two reference axis and is finding respectively a series of M _iand N _i, by its scale value can determine separately corresponding radially with tangential stress, thereby draw distribution curve of stress.

The deformation zone stress RAPID METHOD of other forming mode:

The stress RAPID METHOD of other forming mode and above-mentioned drawing example are basic identical, repeat no more.But note following rule:

1. on the polar diagram in front, different r=f (θ) curve corresponding to forming mode, can not obscure.

Though 2. the border of known stress be deformed area outward flange (for example drawing, sleeve are subject to interior pressure) or in bore edges (for example hole flanging, sleeve are subject to external pressure), always its corresponding points relative coordinate value on polar diagram equals on 1 cylindrical.Whole deformed area, corresponding to the region in cylindrical, can not exceed cylindrical.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (2)

1. look into power dish for one kind, it is characterized in that, described Charlie is coiled the disk of being put upside down mutually by a positive and negative two sides word and is formed, described disk front is the polar diagram of describing the parameter curve r=f (θ) of various forming modes, described coordinate diagram is made up of the radially relative coordinate of angle coordinate and some position, described angular coordinate theta is spent to (+180) by 0 counterclockwise, spends clockwise the radially relative coordinate of described position by 0 to (180)

or

scale be all by 0 to 1, described reverse side is a pair of stress reference axis that is 60 degree obliques, represents respectively radially and the relative value of tangential stress

with

coordinate scale is by 0 to ± 1.155, and described reverse side is also provided with two families respectively perpendicular to the grid lines of stress reference axis separately.

2. the using method of a kind of power of looking into dish as claimed in claim 1.

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