CN103760022A - Stress deformation engineering analysis method of high-flexibility heat-insulation material - Google Patents

Abstract

The invention provides a stress deformation engineering analysis method of a high-flexibility heat-insulation material. The method comprises the following steps of (1) carrying out a standard single-direction compression test on the high-flexibility heat-insulation material on a pressure test machine; (2) drawing a stress-strain curve and performing curve analysis; (3) fitting the parameter of the high-flexibility heat-insulation material by selecting an appropriate constitutive function; (4) calculating the deformation of the high-flexibility heat-insulation material under the stress state according to an interpolation and extrapolation method; (5) performing engineering judging, returning to the step 2 if the calculation result obtained in the step (4) does not meet the engineering reality to re-analyze the curve, select the function, recognize the parameters and calculate, and entering the next step if the calculation result conforms to the engineering practice; and (6) performing engineering applying and popularizing. An engineering method is provided for the stress deformation of the high-flexibility heat-insulation material.

Description

A kind of high flexibility insulation heat-barrier material stress deformation engineering solution analysis method

Technical field

The present invention relates to a kind of high flexibility insulation heat-barrier material normal temperature, high temperature forced deformation computing method, in particular to the Axial compression tests of high flexibility insulation heat-barrier material, material constitutive modeling, material parameter checking and engineering application, belong to materials processing technology field.

Background technology

High flexibility insulation heat-barrier material, owing to having high-temperature stable, flexible covariant, insulation, the plurality of advantages such as heat insulation, therefore, is widely used as bed course in the advanced warm forming of material.Especially when electric current assist formation, due to heat insulation blank and the mould of will insulating, often adopt high flexibility insulation heat-barrier material.But, due to the high flexibility of this material, material stressed with deformation relationship complexity, present nonlinearity, feature such as unloading energy loss etc.; And material stress deformation amount is large, cause the feature that stressed course is large to formation of parts size impact.Meanwhile, course in use, electrically contacts, heat affecting, load coupling, and material usage work condition abnormality complexity, therefore, determines that bed course distortion becomes very difficult to the rule that affects of formation of parts size.

Summary of the invention

The object of the invention is the constitutive model in order to set up high flexibility insulation heat-barrier material stress deformation, and by its application.

The present invention need to set up stressed bed course and be out of shape the rule that affects on formation of parts size, by methods such as Axial compression tests, constitutive modeling, parameter identification, Curve fitting simulation, contrast verifications, determine fast the parameter of high flexibility insulation heat-barrier material, thereby set up the constitutive model of high flexibility insulation heat-barrier material, quantitatively determine that bed course is out of shape the impact on formation of parts size.

The present invention is by the following technical solutions:

(1) for high flexibility insulation heat-barrier material, in the enterprising column criterion compression test of pressure sample machine, obtain the Uniaxial Compression data of material;

(2) the Uniaxial Compression data that obtain according to step (1), this structure of pressure-deformation curve of drafting material, and analyze with regard to curvilinear characteristic;

(3) according to curvilinear characteristic, select suitable constitutive function, adopt " trial and error " parameter of matching high flexibility insulation heat-barrier material;

(4) by the definite material parameter of step (3), bring the constitutive function of step (3) into, determine material constitutive equation; Then according to interpolation Extrapolation method, utilize definite material constitutive equation, calculate the deflection of high flexibility insulation heat-barrier material stress;

(5) engineering judgement.If the result of calculation of step (4) does not meet engineering reality, return to step (2), reanalyse curve, choice function, identification material parameter, calculates; If meet engineering reality, enter next step; (6) set up the constitutive model of high flexibility insulation heat-barrier material, quantitatively determine that bed course be out of shape the impact on formation of parts size, and carried out engineering application and popularization, for the high flexibility heat-barrier material stress deformation that insulate provides a kind of engineering solution analysis method.

Compared with prior art, the advantage of this method is: the thought that has adopted plasto-elasticity constitutive modeling, to high flexibility insulation heat-barrier material modelling, adopt the methods such as constitutive modeling, parameter identification, Curve fitting simulation, contrast verification, determine fast the parameter of high flexibility insulation heat-barrier material, set up the constitutive model of high flexibility insulation heat-barrier material, quantitatively determine that bed course is out of shape the impact on formation of parts size.That this project method has is rapid, low cost, simple and easy to do feature.

Accompanying drawing explanation

Fig. 1 is a kind of process flow diagram of high flexibility insulation heat-barrier material stress deformation engineering solution analysis method;

Fig. 2 is high flexibility insulation heat-barrier material standard Axial compression tests figure:

(a) be compression assay maps;

(b) be compression test machine grip holder figure;

Fig. 3 is the stress-strain diagram of high flexibility insulation heat-barrier material within a compression cycle cycle;

Fig. 4 is the contrast of high flexibility insulation heat-barrier material constitutive equation fitting result and test findings:

(a) comparing result of load phase;

(b) comparing result of unloading phase;

Fig. 5 is equivalent die face schematic diagram after high flexibility insulation heat-barrier material pressurized:

(a) high flexibility insulation heat-barrier material pressurized schematic diagram;

(b) equivalent die face schematic diagram;

Embodiment

Below in conjunction with accompanying drawing 1-5 and instantiation, the present invention is elaborated.

The invention provides high flexibility insulation heat-barrier material stress deformation engineering solution analysis method, its flow process as shown in Figure 1.

Step of the present invention is as follows:

Step 1: high flexibility insulation heat-barrier material is selected Kaowool Paper, and compression experiment equipment adopts the LR30K of Ametek company testing machine, and compression test standard is followed GB/T7757-93.Compression sample thickness is 6mm, and specimen finish Ф=52.5mm is shown in Fig. 2 (a).The speed control of compression test is 10 ± 2mm/min, and compression test working portion is shown in Fig. 2 (b).

Step 2: by drawing OriginPro software, draw the stress-strain diagram of Kaowool material according to Axial compression tests data, see Fig. 3, wherein, horizontal ordinate represents engineering strain, and ordinate represents engineering stress.

Analysis chart 3, can find out that Kaowool material has following characteristic:

1. engineering stress does not have large variation in [0,0.7] scope, maintains low stress level always;

2. engineering stress, in the drastic change of having to go to the toilet of [0.7,0.98] scope, presents violent monotone increasing trend;

3. the loading curve of material is not identical with unloading curve: the elastic modulus of load phase is less than the elastic modulus of unloading phase, therefore,, in the pseudoelasticity stage, a part of elasticity can be transformed into plasticity energy, there is plastic yield in material, this is the significant difference of being out of shape with metal material;

4. after unloading, the plastic yield engineering strain of material is about 0.5.

Unique deformation characteristic of Kaowool (a kind of ceramic fiber paper) material, has determined that its this structure is different from the constitutive model of the elastic materials such as rubber spacer.Up to now, due to the complicacy of ceramic fiber paper applying working condition, the complicacy of material property, the stress-strain diagram of ceramic fiber paper when loading, unloading do not overlap, loading acting causes unloading rear material plastic yield has occurred, therefore its constitutive relation is more complicated, so the document of research ceramic fiber paper constitutive model is little.Only find that the angle of Ramasubramanian M.K. based between material fiber direction and machine direction set up the constitutive model of the unloading behavior of several braided materials of a kind of fibrous paper and other.

Step 3: according to this structure curve non-linear increasing and the feature of successively decreasing, the present invention adopts the constitutive relation of secondary growth form exponential function matching Kaowool material, and fitting function form is shown in formula (1).According to experience, change one by one parameter value, adopt " trial and error " matching material parameter.Finally, equation parameter fitting result is in Table 1, and equation curve fitting result is shown in Fig. 4.

σ=σ ₀+A ₁exp(ε/t ₁)+A ₂exp(ε/t ₂) (1)

The secondary exponential type constitutive equation parameter fitting result of table 1Kaowool material

Stage

σ 0

A 1

t 1

A 2

t 2

R-Square

Load phase

-0.0223

1.585E-4

9.174

1.585E-4

9.174

0.998

Unloading phase

-0.0507

2.061E-8

4.941

2.061E-8

4.941

0.986

Step 4: bring material parameter definite table 1 in step 3 into formula (1) constitutive function, obtain the constitutive equation of material; Then according to interpolation Extrapolation method, can calculate the distortion of action of compressive stress arbitrarily between plate and die-face of high flexibility insulation heat-barrier material.Calculate the deflection of insulating material under maximum working load below, wherein suppose material settling out; Maximum working load (σ _θ) be 200MPa, Kaowool material bears pressure schematic diagram and sees Fig. 5 (a).Kaowool material bearing load is calculated as follows:

${\mathrm{\σ}}^{\mathrm{ins}}={\mathrm{\σ}}_{\mathrm{\θ}}^{\mathrm{she}}\sin \mathrm{\θ}---\left(2\right)$

The maximum load that Kaowool material bears is: ${{\mathrm{\σ}}^{\mathrm{ins}}|}_{\max }={\mathrm{\σ}}_{\mathrm{\θ}}^{\mathrm{she}}{\sin \mathrm{\θ}|}_{\mathrm{\θ}=\mathrm{\α}}=100\left(\mathrm{MPa}\right).$

Wherein, σ ^msthe compressive stress of bearing for insulating material; ${\mathrm{\σ}}_{\mathrm{\θ}}^{\mathrm{she}}$ For plate is in pull-shaped tension of circumferentially bearing; θ be in plate any ${\mathrm{\σ}}_{\mathrm{\θ}}^{\mathrm{she}}$ And the angle between vertical symcenter; α is the maximal value of angle theta.

Step 5: engineering verification.By the constitutive equation of the load phase of maximum pressure load 100MPa substitution Kaowool material, through extrapolation, calculate ε=0.965; Simultaneously, the reduced scale coefficient of considering mold materials (Ni7N) and TC4 material is 6 ‰, when definition is born maximum pressure through Kaowool material, carry out radial thickness compensation and consider that the working surface of mould reduced scale compensation is equivalent die face, see Fig. 3-5 (b).Through over-compensation, the radius of equivalent mould is:

r _e=r _d+δ| _min+ΔL≈593.48+(1-0.965)×6+593.48×6‰≈597mm。Fig. 5 (b) is shown in by equivalence die face schematic diagram.Through finite element and verification experimental verification, above-mentioned equivalent die face radius meets engineering reality.

Step 6: apply.So far, the present invention has calculated the impact of high flexibility insulation heat-barrier material on mold radius; Meanwhile, for ease of through engineering approaches application, high flexibility insulation heat-barrier material is supposed as follows: 1. suppose that insulating material is stable, by the constitutive relation under the replacement high temperature of the constitutive relation under normal temperature; In fact, due to the high-temperature stability of high flexibility insulation heat-barrier material, the error that constitutive relation causes levels off to zero; 2. for simplifying computation model, the mold radius variation that high flexibility insulation heat-barrier material variation in thickness is caused compensates, the foundation by equivalent die face as theory calculating and finite element analysis; 3. equivalent die face is reduced to rigidity workplace, and it calculates the reduced scale coefficient that also needs to consider blank and mold materials.

It is pointed out that the above, is only specific embodiment of the invention example, and the data of using in example and chart are only for illustrating the concrete thought of this method.For a person skilled in the art, within the spirit and principles in the present invention all, the variation that can expect easily or equal replacement, improvement etc., within all should being included in protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of described claim.

Claims (4)

1. a high flexibility insulation heat-barrier material stress deformation engineering solution analysis method, is characterized in that the method comprises the following steps:

(1) for high flexibility insulation heat-barrier material, at the enterprising column criterion normal temperature of material sample machine Axial compression tests, obtain the Uniaxial Compression data of material;

(2) the Uniaxial Compression data that obtain according to step (1), this structure of pressure-deformation curve of drafting material, and analyze with regard to curve;

(3) according to curvilinear characteristic, select suitable constitutive function, adopt " trial and error " parameter of matching high flexibility insulation heat-barrier material;

(4) by the definite material parameter of step (3), bring the constitutive function of step (3) into, determine the constitutive equation of material; Then according to interpolation Extrapolation method, utilize definite constitutive equation, calculate the deflection of high flexibility insulation heat-barrier material stress;

(5) engineering judgement.If the result of calculation of step (4) does not meet engineering reality, return to step (2), reanalyse curve, choice function, identification material parameter, calculates; If meet engineering reality, enter next step; (6) set up the constitutive model of high flexibility insulation heat-barrier material, quantitatively determine that bed course be out of shape the impact on formation of parts size, and carried out engineering application and popularization, for the high flexibility heat-barrier material stress deformation that insulate provides a kind of engineering solution analysis method.

2. a kind of high flexibility insulation heat-barrier material stress deformation engineering solution analysis method according to claim 1, is characterized in that high flexibility insulation heat-barrier material is Kaowool Paper, CT1260Paper.

3. a kind of high flexibility insulation heat-barrier material stress deformation engineering solution analysis method according to claim 1, it is characterized in that the stability due to insulating material, in the permission to use temperature range of material, by the constitutive relation under the approximate replacement high temperature of the constitutive relation under normal temperature.

4. a kind of high flexibility insulation heat-barrier material stress deformation engineering solution analysis method according to claim 1, it is characterized in that " trial and error " that described step (3) is used, need to carry out trial and error according to certain experience, rule, and then determine material parameter rapidly.

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