CN103217335A - Method for rapidly detecting main curve of tensile strength for unidirectional stretching of solid propellant - Google Patents

Abstract

The invention relates to a method for rapidly and quantitatively evaluating spaceflight fuel performances, and relates to a method for rapidly detecting a main curve of tensile strength for unidirectional stretching of a solid propellant. The method comprises eight steps of: analyzing a relation between a dynamic energy storage modulus and a setting, calculating a relation between a stress relax modulus and a setting temperature, drafting a difference graph of a main curve of the dynamic energy storage modulus to a main curve of the stress relax modulus, detecting tensile strength of unidirectional stretching, obtaining a dynamic frequency value, obtaining a dynamic energy storage modulus value, obtaining a tensile strength value of unidirectional stretching, and drafting a main curve map of tensile strength of unidirectional stretching. By detecting the main curve of the dynamic energy storage modulus and the main curve of the stress relax modulus of the solid propellant, and based on a relative formula, the dynamic tensile strength value and the main curve of the tensile strength of the unidirectional stretching are obtained at any temperature and any stretching speed. The method is widely used for rapidly detecting fuel performances of the solid propellant, and has advantages of short detection process, low consumption sample, low test cost and good data repeatability.

Description

The method for quick of solid propellant unilateral stretching tensile strength principal curve

Affiliated technical field

The invention belongs to space flight with so expecting performance rapid quantitatively evaluating method, it utilizes solid propellant dynamic storage modulus principal curve to calculate unilateral stretching tensile strength principal curve, particularly a kind of method for quick of solid propellant unilateral stretching tensile strength principal curve.

Background technology

In the airspace engine field, for solid propellant is carried out the Structural Integrity of Propellant Grains analysis, need obtain the static mechanical parameter such as Relaxation Modulus principal curve, unilateral stretching tensile strength principal curve of solid propellant, usually the method that is adopted is the static mechanical analytic approach, utilize large-scale Material Testing Machine to realize, this testing process has and expends time in, consumes sample and the high defective of experimentation cost.And adopt the dynamic mechanical analysis method to test, have the testing process weak point, consume the advantage that sample is few, experimentation cost is low.

With regard to solid propellant, for the relation between dynamic mechanical and the static mechanical, utilize dynamic complex modulus to ask class problems such as approximate conversion formula of the Relaxation Modulus in the static mechanical parameter, people are also among exploring.

China's " solid-rocket technology " periodical third phase in 2006 has been reported document " solid propellant storage life non-destructive estimation method---dynamic mechanical principal curve monitoring method ", the document has been analyzed the corresponding relation of solid propellant dynamic storage modulus principal curve and Relaxation Modulus principal curve and unilateral stretching tensile strength principal curve, has proposed dynamic storage modulus principal curve and Relaxation Modulus and has had constant difference relation.

China's " war industry's journal " periodical third phase nineteen ninety-five has been reported document " engineering method of Relaxation Modulus and dynamic complex modulus conversion Calculation ", the document has proposed dynamic complex modulus principal curve and Relaxation Modulus principal curve should differ function item about the load time rather than constant term.

China's " Push Technology " periodical fifth phase in 2010 has been reported document " research of solid propellant dynamic storage modulus principal curve calculated stress relaxation modulus ", the document has been analyzed the dynamic storage modulus that utilizes in the one-dimensional linear Theory of Viscoelasticity and the relation of Relaxation Modulus, has derived the numerical method of utilizing solid propellant dynamic storage modulus principal curve to calculate and revise the Relaxation Modulus principal curve.

Above document is explored the relation between dynamic storage modulus principal curve and the Relaxation Modulus principal curve, does not utilize the dynamic storage modulus principal curve to estimate that the static mechanical parameter is the concrete grammar of unilateral stretching tensile strength principal curve but all relate to.Unilateral stretching tensile strength principal curve is a significant data, and it can judge engine under the specified load effect, whether can satisfy the structural intergrity requirement of solid propellant.Therefore, at the solid propellant of present widespread use, be necessary to develop a kind of method that the dynamic storage modulus principal curve calculates unilateral stretching tensile strength principal curve of passing through of practicality.

Summary of the invention

The objective of the invention is to provide the method for quick of solid propellant unilateral stretching tensile strength principal curve.It utilizes solid propellant dynamic storage modulus principal curve to calculate unilateral stretching tensile strength principal curve, can analyze the numerical relation of solid propellant dynamic storage modulus principal curve and unilateral stretching tensile strength principal curve effectively, draw its static mechanical parameter by detection, promptly by advancing the detection of dynamic storage modulus principal curve to draw unilateral stretching tensile strength principal curve to solid to the solid propellant dynamic mechanics parameter.

Technical scheme of the present invention is: design a kind of method for quick of solid propellant unilateral stretching tensile strength principal curve, it utilizes solid propellant dynamic storage modulus principal curve to calculate unilateral stretching tensile strength principal curve, comprises following eight steps:

Step 1, analyze dynamic storage modulus and the relation of setting dynamic frequency: utilize the dynamic mechanical analysis instrument, measure the solid propellant sample a series of design temperatures, set dynamic frequency storage modulus E ＇ (ω) down, according to the time-the Wen equivalence principle, superposeing obtains reference temperature T _sUnder the dynamic storage modulus principal curve, obtain E ＇ (ω)-ω relation curve;

Step 2, the relation of calculated stress relaxation modulus and design temperature: utilize Material Testing Machine, requirement by China Aerospace industrial standard QJ 2487-1993 " composite solidpropellant unilateral stretching Relaxation Modulus and principal curve assay method thereof ", Relaxation Modulus principal curve to the solid propellant sample detects, and obtains E (t)-t relation curve;

Step 3, the differential chart of drafting dynamic storage modulus principal curve and Relaxation Modulus principal curve: according to formula

, can learn the relation of time t and dynamic frequency ω dynamic storage modulus principal curve and Relaxation Modulus principal curve to be drawn in the same coordinate system that the difference that draws two curves changes with t, promptly obtains formula lgE ＇ (ω)-lgE (t)=a+b * c ^LgtIn a, b, c value;

Step 4 detects the unilateral stretching tensile strength sigma ₁: under design temperature and setting draw speed, detect the unilateral stretching tensile strength sigma of solid propellant sample ₁Value is set reference temperature and can be chosen T ₁=20+273=293K sets draw speed and can choose V=100mm/min;

Step 5, obtain dynamic frequency ω value: the strain rate R when supposing the solid propellant sample unilateral stretching under solid propellant sample dynamic frequency ω and the relevant temperature equates, according to formula

, wherein l is the solid propellant sample length, draws the dynamic frequency ω value of correspondence when setting draw speed V=100mm/min in the step 4;

Step 6, obtain the dynamic storage modulus value: according to E ＇ (ω)-ω relation curve, utilize the dynamic frequency ω value in the step 5, obtain the dynamic storage modulus under design temperature and the setting draw speed, design temperature can be chosen one from-50 ℃～70 ℃, set draw speed and can choose one from 0.5～500mm/min.

Step 7 is obtained unilateral stretching tensile strength values σ ₂: according to formula , with storage modulus E ＇ (ω), time t, dynamic frequency ω and a, b, the c value is the substitution formula respectively, draws design temperature of choosing in the step 6 and the unilateral stretching tensile strength values σ that sets under the draw speed ₂

Step 8, draw unilateral stretching tensile strength principal curve figure: repeat above step 5, step 6, step 7, draw the unilateral stretching tensile strength values under a series of design temperatures and the setting draw speed, make ordinate with the unilateral stretching tensile strength values, dynamic frequency ω makes horizontal ordinate, makes unilateral stretching tensile strength principal curve figure.

The invention has the beneficial effects as follows: the present invention is owing to utilize the dynamic mechanical analysis instrument, measure a series of design temperatures of solid propellant sample, the dynamic storage modulus E ＇ (ω) under the setting dynamic frequency, thereby analyzed the relation between solid propellant dynamic storage modulus and the dynamic frequency effectively.Simultaneously owing to utilize Material Testing Machine that the Relaxation Modulus principal curve of solid propellant sample is detected, thereby can obtain solid propellant Relaxation Modulus and the relation between the time.In addition because according to formula , can draw the unilateral stretching tensile strength values under any design temperature and the setting draw speed, thereby can make ordinate with dynamic tensile strength values, ω makes horizontal ordinate with dynamic frequency, makes unilateral stretching tensile strength principal curve figure.The present invention compared with prior art also has following advantage:

The consumption of testing process sample is less, experimentation cost is low: the present invention by series of computation obtain solid propellant at design temperature and set unilateral stretching tensile strength values under the draw speed, thereby obtain the tensile strength principal curve, measuring solid propellant tensile strength principal curve with direct employing Material Testing Machine compares, the amount of samples reduction surpasses 100 times, has saved cost greatly.

Computing method are simple, detection efficiency is higher: the present invention is simple to the computing method of unilateral stretching tensile strength principal curve, measuring solid propellant tensile strength principal curve with direct employing Material Testing Machine compares, the time of cost shortens greatly, thereby has improved efficiency of measurement.

Test practical, data good reproducibility: a large number of experiments show that, the solid propellant tensile strength principal curve that adopts the inventive method to obtain is compared with direct employing Material Testing Machine measurement result, the two is very approaching, can substitute with the inventive method fully, so the present invention has stronger practicality.

Description of drawings

Fig. 1 is that solid propellant is at design temperature T _sDynamic storage modulus E ＇ (ω) principal curve in the time of=20 ℃;

Fig. 2 is Relaxation Modulus E (t) principal curve of solid propellant in the time of design temperature Ts=20 ℃;

Fig. 3 is the difference change curve of t in time of solid propellant dynamic storage modulus and two principal curves of Relaxation Modulus;

Fig. 4 is the comparison diagram of solid propellant dynamic tensile strength principal curve calculated value and measured value.

Table 1 is to utilize the stress value table of comparisons under 0 ℃ of different stretch speed of solid propellant dynamic modulus principal curve match.

Embodiment

The embodiment that provides below in conjunction with accompanying drawing divides three parts, and the present invention is further described.

The first, detect principle.

According to the one-dimensional linear Theory of Viscoelasticity, dynamic storage modulus and Relaxation Modulus have following theory relation:

$E\left(t\right)=E_e+\frac{2}{\mathrm{\π}}{\∫}_0^{\∞}\frac{E^{\′}\left(\mathrm{\ω}\right)-E_e}{\mathrm{\ω}}\sin \mathrm{\ωtd\ω}---\left(1\right)$

In the formula, E (t) is a Relaxation Modulus, and ω is a dynamic frequency, and E ＇ (ω) is a dynamic storage modulus, E _eBe equilibrium modulus, go out because formula (1) is difficult to integration, therefore seek approximate conversion formula, according to prior art, the solid propellant match draws and has following relation between dynamic storage modulus, the Relaxation Modulus

$E\left(t\right)=0.2817\exp [-(0.108+0.115\mathrm{lgt})]E^{\′}\left(\mathrm{\ω}\right){|}_{\mathrm{\ω}=2/\mathrm{\πt}}---\left(2\right)$

(2) formula is transformed,

$\mathrm{lgE}\left(t\right)-\lg E^{\′}\left(\mathrm{\ω}\right)=0.597-0.00651\mathrm{lgt}---\left(3\right)$

Be that dynamic storage modulus and Relaxation Modulus differ a function about time t, need add the conversion of shifted divisor during actual computation.For different solid propellants, the form of expression of function should be different with value.

For solid propellant,, draw through to dynamic storage modulus principal curve and the match of Relaxation Modulus principal curve difference

$\lg E^{\′}\left(\mathrm{\ω}\right)-\mathrm{lgE}\left(t\right)=0.48-0.13\×{0.5}^{\mathrm{lgt}}---\left(4\right)$

As generalized case,

$\lg E^{\′}\left(\mathrm{\ω}\right)-\mathrm{lgE}\left(t\right)=a+b\×c^{\mathrm{lgt}}---\left(5\right)$

In the formula, a, b, c are constant.Because solid propellant is particles filled viscoelastic material, initially has a lot of cavities and defective, according to following equation,

$\mathrm{\σ}={\left(\frac{2\mathrm{\γE}}{\mathrm{\πc}}\right)}^{1/2}---\left(6\right)$

In the formula, γ is a material surface energy, and c is the crackle radius, and E is an elastic modulus.To same solid propellant prescription, γ and c are constant substantially, so σ ∝ E ^1/2So, the ratio of the stress of solid propellant under different temperatures, different stretch speed should with corresponding modulus root mean square than corresponding, this modulus is a time t function, promptly

$\frac{E_1{\left(t_1\right)}^{1/2}}{E_2{\left(t_2\right)}^{1/2}}=\frac{{\mathrm{\σ}}_1}{{\mathrm{\σ}}_2}---\left(7\right)$

Because the modulus of material is all relevant with environment temperature with intensity, so stress need multiply by temperature conversion amount T _s/ T, so (7) formula becomes:

$\frac{E_1{\left(t_1\right)}^{1/2}}{E_2{\left(t_2\right)}^{1/2}}=\frac{{\mathrm{\&sigma;}}_1\&CenterDot;T_s/{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="121012154313.png,121012154318.png"\; state="\{\{state\}\}">T</figure-callout>}}_1}{{\mathrm{\&sigma;}}_2\&CenterDot;T_s/T_2}---\left(8\right)$

Formula (5) substitution formula (8) is got

$\frac{{\left[{10}^{(\lg E^{\&prime;}\left({\mathrm{\&omega;}}_1\right)-a-b\&times;c^{\lg t_1})}\right]}^{1/2}}{{[{10}^{(\lg E^{\&prime;}\left({\mathrm{\&omega;}}_2\right)-a-b\&times;c^{{\mathrm{lgt}}_2})]}}^{1/2}}=\frac{{\mathrm{\&sigma;}}_1{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="121012154313.png,121012154318.png"\; state="\{\{state\}\}">T</figure-callout>}}_2}{{\mathrm{\&sigma;}}_1{T}_1}---\left(9\right)$

Formula (9) is the relational expression between dynamic storage modulus and the unilateral stretching tensile strength, utilize experiment test to get solid propellant dynamic storage modulus principal curve and Relaxation Modulus principal curve, utilize the unilateral stretching experiment simultaneously, draw the solid propellant sample and setting reference temperature T ₁With setting draw speed V ₁Under unilateral stretching tensile strength values σ ₁, can draw solid propellant tensile strength principal curve as follows.

The second, calculate and drawing.

Step 1 is analyzed dynamic storage modulus and the relation of setting dynamic frequency.Utilize the dynamic mechanical analysis instrument, measure the solid propellant sample a series of design temperatures, set dynamic frequency storage modulus E ＇ (ω) down, according to the time-the Wen equivalence principle, superposeing obtains reference temperature T _sUnder the storage modulus principal curve, obtain E ＇ (ω)-ω relation curve and temperature shifted divisor lg α under the different set temperature _tValue.

Step 2, the relation of calculated stress relaxation modulus and design temperature: utilize Material Testing Machine, requirement by China Aerospace industrial standard QJ 2487-1993 " composite solidpropellant unilateral stretching Relaxation Modulus and principal curve assay method thereof ", Relaxation Modulus principal curve to the solid propellant sample detects, and obtains E (t)-t relation curve.

Step 3, the differential chart of drafting dynamic storage modulus principal curve and Relaxation Modulus principal curve: according to formula

, can learn the relation of time t and dynamic frequency ω dynamic storage modulus principal curve and Relaxation Modulus principal curve to be drawn in the same coordinate system that the difference that draws two curves changes with t, promptly obtains formula lgE ＇ (ω)-lgE (t)=a+b * c ^LgtIn a, b, c value.

Step 4 detects the unilateral stretching tensile strength sigma ₁: under design temperature and setting draw speed, detect the unilateral stretching tensile strength sigma of solid propellant sample ₁Value is set reference temperature and can be chosen T ₁=20+273=293K sets draw speed and can choose V=100mm/min.

Step 5, obtain dynamic frequency ω value: the strain rate R when supposing the solid propellant sample unilateral stretching under solid propellant sample dynamic frequency ω and the relevant temperature equates, according to formula

, wherein l is the solid propellant sample length, draws the dynamic frequency ω value of correspondence when setting draw speed V=100mm/min in the step 4.

Step 6, obtain the dynamic storage modulus value: according to E ＇ (ω)-ω relation curve, utilize the dynamic frequency ω value in the step 5, obtain the dynamic storage modulus under design temperature and the setting draw speed, design temperature can be chosen one from-50 ℃～70 ℃, set draw speed and can choose one from 0.5～500mm/min.

Step 7 is obtained unilateral stretching tensile strength values σ ₂: according to formula

, with storage modulus E ＇ (ω), time t, dynamic frequency ω and a, b, the c value is the substitution formula respectively, draws design temperature of choosing in the step 6 and the unilateral stretching tensile strength values σ that sets under the draw speed ₂

Step 8, draw unilateral stretching tensile strength principal curve figure: repeat above step 5, step 6, step 7, draw the unilateral stretching tensile strength values under a series of design temperatures and the setting draw speed, make ordinate with the unilateral stretching tensile strength values, dynamic frequency ω makes horizontal ordinate, makes unilateral stretching tensile strength principal curve figure.

The 3rd, detect example and data processing.

Embodiment 1: the solid propellant sample is for to take a sample from the solid propellant square billet.

Step 1 is analyzed dynamic storage modulus and the relation of setting dynamic frequency.Utilize the dynamic mechanical analysis instrument, measure the solid propellant sample a series of design temperatures, set dynamic frequency storage modulus E ＇ (ω) down, according to the time-the Wen equivalence principle, superposeing obtains reference temperature T _sUnder the storage modulus principal curve, obtain E ＇ (ω)-ω relation curve, Fig. 1 is and utilizes solid propellant that the dynamic mechanical analysis instrument draws at design temperature T _sDynamic storage modulus E ＇ (ω) principal curve in the time of=20 ℃; And draw shifted divisor lg α under the different set temperature _tValue, when for example design temperature is 0 ℃, lg α _t=1.09.

Step 2, the relation of calculated stress relaxation modulus and design temperature: utilize Material Testing Machine, requirement by China Aerospace industrial standard QJ 2487-1993 " composite solidpropellant unilateral stretching Relaxation Modulus and principal curve assay method thereof ", Relaxation Modulus principal curve to the solid propellant sample detects, obtain E (t)-t relation curve, Fig. 2 utilizes the Material Testing Machine test to draw Relaxation Modulus E (t) principal curve of solid propellant in the time of design temperature Ts=20 ℃.

Step 3, the differential chart of drafting dynamic storage modulus principal curve and Relaxation Modulus principal curve: according to formula

, can learn the relation of time t and dynamic frequency ω dynamic storage modulus principal curve and Relaxation Modulus principal curve to be drawn in the same coordinate system that the difference that draws two curves changes with t, promptly obtains formula lgE ＇ (ω)-lgE (t)=a+b * c ^LgtIn a, b, c value; Fig. 3 is the difference change curve of t in time of solid propellant dynamic storage modulus principal curve and Relaxation Modulus principal curve, can draw a=0.48 from Fig. 3 curve, b=-0.13, c=0.5.

Step 4 detects the unilateral stretching tensile strength sigma ₁: under design temperature and setting draw speed, detect the unilateral stretching tensile strength sigma of solid propellant sample ₁Value is set reference temperature and can be chosen T ₁=20+273=293K sets draw speed and can choose V=100mm/min, detects the unilateral stretching tensile strength sigma of solid propellant sample ₁=0.82MPa.

Step 5, obtain dynamic frequency ω value: the strain rate R when supposing the solid propellant sample unilateral stretching under solid propellant sample dynamic frequency ω and the relevant temperature equates, according to formula

Wherein l is the solid propellant sample length, draw the dynamic frequency ω logarithm value of correspondence when setting draw speed V=100mm/min in the step 4, draw lg ω=0.15, the dynamic frequency ω logarithm value result of calculation that table 1 has been listed correspondence when the setting draw speed is respectively 2mm/min, 20mm/min, 100mm/min, 500mm/min is followed successively by-1.54 ,-0.54,0.15,0.85.

Step 6, obtain the dynamic storage modulus value: according to E ＇ (ω)-ω relation curve, utilize the dynamic frequency ω value in the step 5, obtain the dynamic storage modulus under design temperature and the setting draw speed, design temperature can be chosen one from-50 ℃～70 ℃, set draw speed and can choose one from 0.5～500mm/min.According to dynamic frequency ω value, from E ＇ (ω)-ω graph of a relation, read E ＇ (ω) value.For example the dynamic frequency value of taking the logarithm lg ω=0.15 o'clock adds corresponding shifted divisor lg α _t, this moment lg (ω α _tLg E ＇ (ω)=0.768 is read in)=1.248 from E ＇ (ω)-ω graph of a relation.Table 1 is for utilizing the stress value table of comparisons under 0 ℃ of different stretch speed of solid propellant dynamic modulus principal curve match, and the dynamic storage modulus value of having listed correspondence when the setting draw speed is respectively 2mm/min, 20mm/min, 100mm/min, 500mm/min in the table 1 is followed successively by 0.400,0.590,0.768,0.944.

Step 7 is obtained unilateral stretching tensile strength values σ ₂: according to formula

, with storage modulus E ＇ (ω), time t, dynamic frequency ω and a, b, the c value is the substitution formula respectively, draws design temperature of choosing in the step 6 and the unilateral stretching tensile strength values σ that sets under the draw speed ₂Promptly drawing design temperature is 0 ℃, when the setting draw speed is 100mm/min, calculates unilateral stretching tensile strength values σ ₂=1.10Mpa.

Step 8, draw unilateral stretching tensile strength principal curve figure: repeat above step 5, step 6, step 7, draw the unilateral stretching tensile strength values under a series of design temperatures and the setting draw speed, make ordinate with the unilateral stretching tensile strength values, dynamic frequency ω makes horizontal ordinate, makes unilateral stretching tensile strength principal curve figure.

Present embodiment is only listed 0 ℃ of calculated value under the different stretch speed.Because requiring tensile strength when unilateral stretching tensile strength principal curve is drawn is the value of taking the logarithm after the temperature conversion, therefore, with unidirectional stretching tensile strength values temperature conversion back tabulation under 0 ℃ of different stretch speed, table 1 is for utilizing the stress value table of comparisons under 0 ℃ of different stretch speed of solid propellant dynamic modulus principal curve match.Make ordinate with the unilateral stretching tensile strength values, dynamic frequency ω makes horizontal ordinate, makes unilateral stretching tensile strength principal curve figure, and Fig. 4 is the comparison diagram of solid propellant dynamic tensile strength principal curve calculated value and measured value.Draw from Fig. 4, result of calculation and experiment test result are very approaching in scope of experiment.

Table 1: utilize stress value under 0 ℃ of different stretch speed of solid propellant dynamic modulus principal curve match

Claims (1)

1. the method for quick of a solid propellant unilateral stretching tensile strength principal curve, it utilizes solid propellant dynamic storage modulus principal curve to calculate unilateral stretching tensile strength principal curve, it is characterized in that, comprises following eight steps:

Step 1, analyze dynamic storage modulus and the relation of setting dynamic frequency: utilize the dynamic mechanical analysis instrument, measure the solid propellant sample a series of design temperatures, set dynamic frequency storage modulus E ＇ (ω) down, according to the time-the Wen equivalence principle, superposeing obtains reference temperature T _sUnder the dynamic storage modulus principal curve, obtain E ＇ (ω)-ω relation curve;

Step 2, the relation of calculated stress relaxation modulus and design temperature: utilize Material Testing Machine, requirement by China Aerospace industrial standard QJ 2487-1993 " composite solidpropellant unilateral stretching Relaxation Modulus and principal curve assay method thereof ", Relaxation Modulus principal curve to the solid propellant sample detects, and obtains E (t)-t relation curve;

Step 3, the differential chart of drafting dynamic storage modulus principal curve and Relaxation Modulus principal curve: according to formula

, can learn the relation of time t and dynamic frequency ω dynamic storage modulus principal curve and Relaxation Modulus principal curve to be drawn in the same coordinate system that the difference that draws two curves changes with t, promptly obtains formula lgE ＇ (ω)-lgE (t)=a+b * c ^LgtIn a, b, c value;

Step 4 detects the unilateral stretching tensile strength sigma ₁: under design temperature and setting draw speed, detect the unilateral stretching tensile strength sigma of solid propellant sample ₁Value is set reference temperature and can be chosen T ₁=20+273=293K sets draw speed and can choose V=100mm/min;

Step 5, obtain dynamic frequency ω value: the strain rate R when supposing the solid propellant sample unilateral stretching under solid propellant sample dynamic frequency ω and the relevant temperature equates, according to formula

, wherein l is the solid propellant sample length, draws the dynamic frequency ω value of correspondence when setting draw speed V=100mm/min in the step 4;

Step 6, obtain the dynamic storage modulus value: according to E ＇ (ω)-ω relation curve, utilize the dynamic frequency ω value in the step 5, obtain the dynamic storage modulus under design temperature and the setting draw speed, design temperature can be chosen one from-50 ℃～70 ℃, set draw speed and can choose one from 0.5～500mm/min.

Step 7 is obtained unilateral stretching tensile strength values σ ₂: according to formula

, with storage modulus E ＇ (ω), time t, dynamic frequency ω and a, b, the c value is the substitution formula respectively, draws design temperature of choosing in the step 6 and the unilateral stretching tensile strength values σ that sets under the draw speed ₂

Step 8, draw unilateral stretching tensile strength principal curve figure: repeat above step 5, step 6, step 7, draw the unilateral stretching tensile strength values under a series of design temperatures and the setting draw speed, make ordinate with the unilateral stretching tensile strength values, dynamic frequency ω makes horizontal ordinate, makes unilateral stretching tensile strength principal curve figure.

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