CN103743671A - Bonding strength checking method for vehicle adhesive - Google Patents

Abstract

The invention discloses a bonding strength checking method for a vehicle adhesive. The method comprises the following steps: calculating the complete stress of an adhesive layer unit on a bonding plane according to a formula shown in the specification, calculating the limit stress of the adhesive layer unit according to a formula shown in the specification, and calculating according to the formula that 1-R=1-p'/p'' to judge the safety. The method can be used for checking bonding strength of a vehicle bonding structure under any complex working conditions. When the working conditions of the bonding structure are determined, the safety of the bonding structure can be judged according to the checking method disclosed by the invention, and moreover, the bonding structure can reach a safe and reliable state in the ways of adjusting the bonding structure form, the bonding area, the gluing amount and the like.

Description

A kind of bonding strength check method of automobile-used bonding agent

Technical field

The present invention relates to a kind of bonding agent bonding strength and check field, more specifically, relate to a kind of bonding strength check method that is applied to the automobile-used bonding agent in the fields such as EMU, passenger train, highway passenger vehicle.

Background technology

Adhesive technology is a kind of Material Joining Technology conventional in engineering, adopt adhesive technology to be linked and packed, to have that outward appearance is neat, join domain load distributes (comparing with riveted joint with bolt) relative evenly, suitable material extensively and can realize the plurality of advantages such as foreign material connection.

In recent years, increasing along with industry member new material application, the application of adhesive technology is also more and more extensive.In Vehicle Industry, most bonding way that adopt such as the assembling of body structure and interior material, sound insulating material, heat-barrier material, windscreen and vehicle window.

Chinese Patent Application No. 201110183157.9 discloses a kind of resin bonding strength detecting method.By utilizing this scheme, can improve the detection accuracy of brittle resin bonding strength, therefore, the bonding strength of the characteristic resin that is applicable to enbrittle detects.But, exist operating process complicated, application is not extensively and detect the problems such as defect that exist.

Although adhesive technology has many advantages, but from current research situation, also there is following problem in the research of relevant adhesive technology: (1) bonded joint mechanical property understanding is insufficient, relevant Basic Experiment Study imperfection, accumulate lessly, form unified, complete strength design standard.For example the mensuration (rigid material is to rigid material) of GB-T7124-2008 < < tackifier tensile shear strength, although > > has provided the tensile shear strength method of testing of a kind of rigid material to the bonded part of rigid material, has wherein also been stipulated " this experimentation is not as design data ".(2) for prediction of strength and the method for designing at vehicle body Typical Joints and important bonding position, in engineering, also lack effective research means.(3) not intensity evaluation model, especially the adhesive property evaluation under complex stress condition and varying environment effectively in the CAE numerical simulation analysis of bonded structure, need to carry out probing into of system.

Summary of the invention

The present invention is directed to the problem existing in existing automobile-used bonding agent adhesive technology, utilize automobile-used bonded structure bondline thickness thinner, glue-line especially with the most outstanding feature of shear stress in glue-line mormal stress and plane, proposes a kind of bonding strength check method based on shear stress in bonding plane normal normal stress and plane under the force-bearing situation of various complexity.

A bonding strength check method for automobile-used bonding agent, step 1, the bonding angle of the many groups of making are respectively α _nautomobile-used bonding test specimen, it is carried out to tension failure experiment; Step 2, according to the automobile-used bonding test specimen of many group different bonding angles suffered normal stress σ, shear stress τ described point in coordinate system when rupture failure, form a critical broken line of bonding agent rupture failure based on normal stress and shear stress; Step 3, by the discrete unit that changes into of automobile-used bonding test specimen to be detected, i.e. glue-line unit, calculating glue-line unit mormal stress is that σ ' and shearing stress are τ ', glue-line unit is in the total stress of bonding plane:

step 4, drawing of glue-line unit are cut than R ' _{σ τ}=σ '/τ ', the line expression formula of glue-line unit and true origin is: y=R ' _{σ τ}x; The mormal stress of the intersection point of this line and the critical broken line of described rupture failure is σ " and shearing stress is τ "; The ultimate stress that glue-line unit can bear

step 5, R=p '/p ", 1-R=1-p '/p "; Get 0≤β ₁< β ₂< 1, if 1-R < 0 represents that the stress that glue-line unit bears has surpassed ultimate stress, this glue-line unit is in explosive area; If 0≤1-R < is β ₁, representing that the stress margin of safety of glue-line unit is not enough, this glue-line unit is in warning area; If β ₁≤ 1-R < β ₂, representing that the stress margin of safety of glue-line unit is suitable, this glue-line unit is in place of safety; If β ₂≤ 1-R < 1, represents that the stress margin of safety of glue-line unit is excessive, and this glue-line unit is in low stress area; β ₁, β ₂for fixed constant.

As further preferably, according to automobile-used operating mode, described β ₁=20% and β ₂=50%.

As further preferred, described α _nfor being more than or equal to 0 and be less than or equal to 90 degree.

As further preferred, bonding angle [alpha] _nbe respectively 0 °, 15 °, 30 °, 45 °, 60 °, 75 °, 90 °.

Beneficial effect:

Automobile-used bonding agent bonding strength check method of the present invention, can carry out bonding strength check to the vehicle bonded structure under any complex working conditions.

In the situation that working condition that bonded structure bears is definite, can judge whether safety of bonded structure according to check method of the present invention, and by adjusting the approach such as bonded structure form, bond area, glue-spread, make bonded structure reach safe and reliable state.

In the situation that the conditions such as bonded structure form, bond area, glue-spread are definite, can utilize that check method of the present invention is Converse solved goes out maximum safe load and the ultimate load that bonded structure can bear.

Accompanying drawing explanation

Fig. 1 is that bonding angle is test specimen mormal stress, the plane shear stress schematic diagram of α.

Fig. 2 is the bonding experiment test specimen of the different bonding angle that adopts in embodiment.

Fig. 3 is the experimental data that bonding test specimen tension failure is destroyed.

Fig. 4 is the critical broken line of bonding agent rupture failure.

Fig. 5 is that schematic diagram is divided in the critical broken line state of strength of bonding agent rupture failure region.

Fig. 6 is EMU vehicle window bonded structure schematic diagram

Fig. 7 is that vehicle window bonded structure Model load applies schematic diagram.

Fig. 8 is a certain glue-line unit strength check schematic diagram.

Fig. 9 is the strength check result of vehicle window bonded structure glue-line unit.

Wherein, 1 for bonding angle be 0 ° experiment test specimen, 2 for bonding angle be 15 ° experiment test specimen, 3 for bonding angle be 30 ° experiment test specimen, 4 for bonding angle be 45 ° experiment test specimen, 5 for bonding angle be 60 ° experiment test specimen, 6 for bonding angle be 75 ° experiment test specimen, 7 for bonding angle be that the experiment test specimen, 8 of 90 ° is for low stress zones, 9 is for safety zone, 10 is for warning region, 11 is for hazardous location, 12 is for side window glass, 13 is for side window aluminum alloy frame, 14 is for bonding glue-line, 15 is for body construction.

Embodiment

The embodiment providing below in conjunction with accompanying drawing is described in further detail the present invention.

The ratio of shear stress τ in mormal stress σ when as shown in Figure 1, bonded adhesives fault rupture destroys and plane compares R for drawing to cut _{σ τ}.Making n organizes bonding angle and is respectively α _nbonding test specimen, it is carried out to tension failure experiment.The i of take organizes bonding test specimen as example, and its bonding angle is α _i, during rupture failure, mormal stress is σ _i, the shear stress in plane is τ _i:

(R _στ) _i＝tanα _i＝σ _i/τ _i 1≤i≤n

Convenience of calculation for follow-up, defines in the present invention:

0=α ₁< α ₂< ... < α _n-1< α _n=pi/2 n>=2 and n are integer

For exemplary illustrated, set up seven groups of bonding agent stretching experiment test specimens that bonding angle is respectively 0 °, 15 °, 30 °, 45 °, 60 °, 75 °, 90 °, as shown in Figure 2, the number of every group of bonding test specimen is 15.As a kind of, preferably, after experiment finishes, get rid of indivedual invalid experimental datas and get the mean value of every group of experimental data as normal stress σ and the shear stress τ of this bonding angle lower glue layer destruction, obtain the data as shown in form in Fig. 3.

As shown in Figure 4, the shear stress τ in bonded adhesives layer plane of take is horizontal ordinate, mormal stress σ is that ordinate is set up coordinate system, according to n group different bonding angle test specimen suffered normal stress σ, shear stress τ described point in coordinate system when the rupture failure, can draw successively n coordinate points (τ ₁, σ ₁), (τ ₂, σ ₂) ... (τ _n, σ _n), n coordinate points connected successively, form a critical broken line of bonding agent rupture failure based on normal stress and shear stress.

As shown in Figure 4 and Figure 5, respectively n coordinate points on connection coordinate initial point and critical broken line, obtains n bar line segment, n-1 the delta-shaped region of n-1 bar line segment formation on itself and critical broken line.The implication of the slope representative of n bar line segment compares R for drawing to cut _{σ τ}, the length of line segment represents that bonding glue-line draws to cut at this and compares R _{σ τ}ultimate stress under state, is defined as p, therefore

$p=\sqrt{{\mathrm{\&tau;}}^2+{\mathrm{\&sigma;}}^2}$

By the discrete unit that changes into of experiment test specimen to be detected, glue-line unit, according to the mechanics of materials, can ask for the stress state of any one glue-line unit center point, i.e. σ _x, σ _y, σ _z, τ _yz, τ _zx, τ _xy.According to the relation of bonding glue-line unit local coordinate system and bonded structure model global coordinate system, the stress value of unit center point is carried out to changes in coordinates, obtain the normal stress of glue-line unit normal direction and the shear stress in plane.The outer normal direction of supposing the bonding plane in a certain glue-line unit is n ', and its direction cosine are:

cos(n′,x)＝l,cos(n′,y)＝m,cos(n′,z)＝n

Defining this glue-line unit is p ' in the total stress of its bonding plane, the p ' for projection in coordinate axis _x, p ' _y, p ' _zrepresent.According to equilibrium condition, can obtain

p′ _x＝lσ _x+mτ _xy+nτ _zx

p′ _y＝mσ _y+nτ _yz+lτ _xy

p′ _z＝nσ _z+lτ _zx+mτ _yz

The mormal stress of supposing the bonding plane in glue-line unit is σ ', and shearing stress is τ ',

σ′＝lp′ _x+mp′ _y+np′ _z

${\mathrm{\&tau;}}^{\&prime;}=\sqrt{p_x^{\&prime;2}+p_y^{\&prime;2}+p_z^{\&prime;2}-{\mathrm{\&sigma;}}^{\&prime;2}}$

$p^{\&prime;}=\sqrt{{\mathrm{\&tau;}}^{\&prime;2}+{\mathrm{\&sigma;}}^{\&prime;2}}$

Drawing of this glue-line unit cut than R ' _{σ τ}=σ '/τ ', by its with critical broken line on n coordinate points corresponding draw to cut compare R _{σ τ}compare, if:

(R _στ) _n-1≤R′ _στ≤(R _στ) _n

This glue-line unit (τ ', σ ') in n-1 delta-shaped region, the line segment on the corresponding critical broken line in this region can be by coordinate points (τ _n-1, σ _n-1), (τ _n, σ _n) express, straight line expression formula is:

$y=\left(\frac{{\mathrm{\&sigma;}}_n-{\mathrm{\&sigma;}}_{n-1}}{{\mathrm{\&tau;}}_n-{\mathrm{\&tau;}}_{n-1}}\right)x+\frac{{\mathrm{\&sigma;}}_{n-1}{\mathrm{\&tau;}}_n-{\mathrm{\&sigma;}}_n{\mathrm{\&tau;}}_{n-1}}{{\mathrm{\&tau;}}_n-{\mathrm{\&tau;}}_{n-1}}$

The line expression formula of this glue-line unit and true origin is: y=R ' _{σ τ}x

According to above straight line expression formula, obtain joining (τ ", σ "):

${\mathrm{\&tau;}}^{\&prime;\&prime;}=\frac{{\mathrm{\&tau;}}^{\&prime;}({\mathrm{\&sigma;}}_{n-1}{\mathrm{\&tau;}}_n-{\mathrm{\&sigma;}}_n{\mathrm{\&tau;}}_{n-1})}{{\mathrm{\&sigma;}}^{\&prime;}({\mathrm{\&tau;}}_n-{\mathrm{\&tau;}}_{n-1})-{\mathrm{\&tau;}}^{\&prime;}({\mathrm{\&sigma;}}_n-{\mathrm{\&sigma;}}_{n-1})}$

${\mathrm{\&sigma;}}^{\&prime;\&prime;}=\frac{{\mathrm{\&sigma;}}^{\&prime;}({\mathrm{\&sigma;}}_{n-1}{\mathrm{\&tau;}}_n-{\mathrm{\&sigma;}}_n{\mathrm{\&tau;}}_{n-1})}{{\mathrm{\&sigma;}}^{\&prime;}({\mathrm{\&tau;}}_n-{\mathrm{\&tau;}}_{n-1})-{\mathrm{\&tau;}}^{\&prime;}({\mathrm{\&sigma;}}_n-{\mathrm{\&sigma;}}_{n-1})}$

$p^{\&prime;\&prime;}=\sqrt{{\mathrm{\&tau;}}^{\&prime;\&prime;2}+{\mathrm{\&sigma;}}^{\&prime;\&prime;2}}$

P " be the ultimate stress that this glue-line unit can bear, get:

R＝p′/p″

1-R＝1-p′/p″

The implication of 1-R representative is the margin of safety of bonding glue-line element stress, determines the strength check result of this glue-line unit according to value 1-R size.Get 0≤β ₁< β ₂< 1, if 1-R < 0 represents that the stress that glue-line unit bears has surpassed ultimate stress, this glue-line unit is in explosive area; If 0≤1-R < is β ₁, representing that the stress margin of safety of glue-line unit is not enough, this glue-line unit is in warning area; If β ₁≤ 1-R < β ₂, representing that the stress margin of safety of glue-line unit is suitable, this glue-line unit is in place of safety; If β ₂≤ 1-R < 1, represents that the stress margin of safety of glue-line unit is excessive, and this glue-line unit is in low stress area.β ₁, β ₂value size should be determined according to the concrete applying working condition of bonded structure.

As a kind of preferred, according to the experience in design of automobile-used bonding agent, in the present embodiment, get β ₁=20%, β ₂=50%, the region that is margin of safety 50%≤1-R < 100% of answering of bonding glue-line unit is that the region of low stress area 8,20%≤1-R < 50% is that the region of place of safety 9,0≤1-R < 20% is that the region of warning area 10,1-R < 0 is explosive area 11, as shown in Figure 5.

Exemplary, bonding angle is respectively seven groups of bonding agent stretching experiment test specimens of 0 °, 15 °, 30 °, 45 °, 60 °, 75 °, 90 °; The shear stress τ in bonded adhesives layer plane of take is horizontal ordinate, mormal stress σ is that ordinate is set up coordinate system, according to the experimental data shown in form in Fig. 2 described point line in coordinate system, obtain the critical broken line of bonding agent rupture failure as shown in Figure 3, seven coordinate points are connected respectively at true origin, the critical broken line graph of bonding agent rupture failure can be divided into six regions, as shown in Figure 4, seven lines are corresponding to be drawn to cut and compares R _{σ τ}be followed successively by:

(R _στ) ₁＝0 (R _στ) ₂＝0.27 (R _στ) ₃＝0.58 (R _στ) ₄＝1

(R _στ) ₅＝1.73 (R _στ) ₆＝3.73 (R _στ) ₇＝∞

For exemplary illustrated, the present invention chooses window structure in EMU as bonded structure to be checked.Window structure mainly comprises side window glass (12), side window aluminum alloy frame (13) two parts.Window structure is as sub-unit parts, by the bonding assembling of finishing dealing with of side window aluminum alloy frame (13) and body construction (15), as shown in Figure 6.

Main force-bearing situation according to window structure in EMU operational process, to window structure model imposed load: in order to simulate in motor train unit high-speed cruising process, due to what pressure difference inside and outside vehicle window caused, act on the acting force on glass for vehicle window, on the glass unit at window structure model middle part, apply uniformly distributed load, as shown in Figure 7 (a); The remaining shear force that may exist after bonding in order to simulate window structure and body construction, applies the acting force of a pair of opposite direction, as shown in Figure 7 (b) shows in the diagonal of vehicle window.

According to the mechanics of materials, by calculating the stress state of bonding glue-line unit.Therefrom appoint and get a glue-line unit, according to described bonding glue-line strength check methods, this glue-line unit is checked.Calculate the stress value of this glue-line unit:

σ _x=5.715264e-5Pa τ _xy=1.086516e-5Pa

σ _y=5.747150e-5Pa τ _yz=2.545583e+6Pa

σ _z=3.131656e+6Pa τ _zx=2.545575e+6Pa

This unit bonding plane normal direction cosine is:

l＝0.00 m＝0.00 n＝1.00

According to shear stress method for solving in described glue-line unit mormal stress and plane, can obtain:

τ′＝3.60MPa σ′＝3.13MPa

R′ _στ＝σ′/τ′＝0.8694

$p^{\&prime;}=\sqrt{{\mathrm{\&tau;}}^{\&prime;2}+{\mathrm{\&sigma;}}^{\&prime;2}}=4.77\mathrm{MPa}$

Owing to drawing, cut than size contrast (R _{σ τ}) ₃< R ' _{σ τ}< (R _{σ τ}) ₄, this glue-line unit is arranged in the 3rd delta-shaped region, according to described computing formula solve joining (τ ", σ "):

τ″＝5.76MPa σ″＝5.00MPa

$p^{\&prime;\&prime;}=\sqrt{{\mathrm{\&tau;}}^{\&prime;\&prime;2}+{\mathrm{\&sigma;}}^{\&prime;\&prime;2}}=7.63\mathrm{MPa}$

R＝p′/p″＝0.625

1-R＝0.325＝32.5%

Therefore can judge this glue-line unit is positioned at place of safety, and the stress state that this glue-line unit bears is safe condition.In like manner can carry out strength check to other glue-line unit, obtain vehicle window bonded structure glue-line unit strength check result as shown in Figure 9.

The above-mentioned description to embodiment is can understand and apply the invention for ease of those skilled in the art.Person skilled in the art obviously can easily make various modifications to these embodiment, and General Principle described herein is applied in other embodiment and needn't passes through performing creative labour.Therefore, the invention is not restricted to the embodiment here, those skilled in the art are according to announcement of the present invention, and not departing from the improvement that category of the present invention makes and revise all should be within protection scope of the present invention.

Claims (4)

1. a bonding strength check method for automobile-used bonding agent, is characterized in that:

Step 1, the bonding angle of the many groups of making are respectively α _nautomobile-used bonding test specimen, it is carried out to tension failure experiment;

Step 2, according to the automobile-used bonding test specimen of many group different bonding angles suffered normal stress σ, shear stress τ described point in coordinate system when rupture failure, form a critical broken line of bonding agent rupture failure based on normal stress and shear stress;

Step 3, by the discrete unit that changes into of automobile-used bonding test specimen to be detected, i.e. glue-line unit, calculating glue-line unit mormal stress is that σ ' and shearing stress are τ ', glue-line unit is in the total stress of bonding plane: $p^{\&prime;}=\sqrt{{\mathrm{\&tau;}}^{\&prime;2}+{\mathrm{\&sigma;}}^{\&prime;2}};$

Step 4, drawing of glue-line unit are cut than R ' _{σ τ}=σ '/τ ', the line expression formula of glue-line unit and true origin is: y=R ' _{σ τ}x; The mormal stress of the intersection point of this line and the critical broken line of described rupture failure is σ " and shearing stress is τ "; The ultimate stress that glue-line unit can bear

$p^{\&prime;\&prime;}=\sqrt{{\mathrm{\&tau;}}^{\&prime;\&prime;2}+{\mathrm{\&sigma;}}^{\&prime;\&prime;2}};$

Step 5, R=p '/p ", 1-R=1-p '/p "; Get 0≤β ₁< β ₂< 1, if 1-R < 0 represents that the stress that glue-line unit bears has surpassed ultimate stress, this glue-line unit is in explosive area; If 0≤1-R < is β ₁, representing that the stress margin of safety of glue-line unit is not enough, this glue-line unit is in warning area; If β ₁≤ 1-R < β ₂, representing that the stress margin of safety of glue-line unit is suitable, this glue-line unit is in place of safety; If β ₂≤ 1-R < 1, represents that the stress margin of safety of glue-line unit is excessive, and this glue-line unit is in low stress area; β ₁, β ₂for fixed constant.

2. the bonding strength check method of automobile-used bonding agent according to claim 1, is characterized in that: according to automobile-used operating mode, and described β ₁=20% and β ₂=50%.

3. the bonding strength check method of automobile-used bonding agent according to claim 1 and 2, is characterized in that: described α _nfor being more than or equal to 0 and be less than or equal to 90 degree.

4. the bonding strength check method of automobile-used bonding agent according to claim 3, is characterized in that: bonding angle [alpha] _nbe respectively 0 °, 15 °, 30 °, 45 °, 60 °, 75 °, 90 °.

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