CN103743671B - 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 vehicle adhesive

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 being applied to the vehicle adhesive 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, have that outward appearance is neat, join domain load diatibution (comparing with riveted joint with bolt) is relatively uniform, suitable material extensively and can the plurality of advantages such as dissimilar material joining be realized.

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, the majority such as the assembling of body structure and interior material, sound insulating material, heat-barrier material, windscreen and vehicle window adopts bonding way.

Chinese Patent Application No. 201110183157.9 discloses a kind of resin bonding strength detecting method.By utilizing the program, 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 there is operating process complexity, application is not extensive and detect the problems such as existing defects.

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

Summary of the invention

The present invention is directed to Problems existing in existing vehicle adhesive adhesive technology, utilize automobile-used bonded structure bondline thickness thinner, glue-line especially with the feature that shear stress in glue-line mormal stress and plane is given prominence to the most, 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 vehicle adhesive, step 1, the bonding angle of the many groups of making are respectively α _nautomobile-used bonding test specimen, tension failure experiment is carried out to it; Step 2, normal stress σ, the shear stress τ in a coordinate system described point suffered when rupture failure according to the automobile-used bonding test specimen of many group different bonding angles, form a critical broken line of bonding agent rupture failure based on normal stress and shear stress; Step 3, change into unit, i.e. glue-line unit by discrete for automobile-used bonding test specimen to be detected, to calculate glue-line unit mormal stress be σ ' and shearing stress is τ ', and 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, represent the stress that glue-line unit bears and exceeded ultimate stress, this glue-line unit is in explosive area; If 0≤1-R < is β ₁, the stress margin of safety representing glue-line unit is not enough, and this glue-line unit is in warning area; If β ₁≤ 1-R < β ₂, the stress margin of safety representing glue-line unit is suitable, and this glue-line unit is in place of safety; If β ₂≤ 1-R < 1, the stress margin of safety representing 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 being less than or equal to 90 degree.

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

Beneficial effect:

Vehicle adhesive bonding strength check method of the present invention, can carry out bonding strength check to the vehicle bonded structure under any complex working conditions.

When working condition that bonded structure bears is determined, bonded structure whether safety can be judged according to check method of the present invention, and by approach such as adjustment bonded structure form, bond area, glue-spreads, make the state that bonded structure reaches safe and reliable.

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

Accompanying drawing explanation

Test specimen mormal stress, the plane shear stress schematic diagram of Fig. 1 to be bonding angle be α.

Fig. 2 is the bonding experiment test specimen of the different bonding angle adopted 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 bonding agent rupture failure critical broken line state of strength Region dividing schematic diagram.

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 structural adhesive layer unit.

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

Embodiment

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

As shown in Figure 1, mormal stress σ when bonded adhesives fault rupture destroys compares R with the ratio of the shear stress τ in plane for drawing to cut _{σ τ}.Make the bonding angle of n group and be respectively α _nbonding test specimen, tension failure experiment is carried out to it.For i-th group of bonding test specimen, its bonding angle is α _i, during rupture failure, mormal stress is σ _i, shear stress in plane is τ _i, then:

(R _στ) _i＝tanα _i＝σ _i/τ _i1≤i≤n

In order to follow-up convenience of calculation, define in the present invention:

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

In order to 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 often organizing bonding test specimen is 15.Preferred as one, after experiment terminates, get rid of experimental data invalid individually and get the normal stress σ and shear stress τ that the mean value of often organizing experimental data destroys as this bonding angle lower glue layer, obtaining the data as shown in form in Fig. 3.

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

As shown in Figure 4 and Figure 5, n coordinate points respectively on connection coordinate initial point and critical broken line, obtains n bar line segment, and the n-1 bar line segment on itself and critical broken line forms n-1 delta-shaped region.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 bonding glue-line and draws to cut compare R at this _{σ τ}ultimate stress under state, is defined as p, therefore

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

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

cos(n′,x)＝l,cos(n′,y)＝m,cos(n′,z)＝n

Defining this glue-line unit in the total stress of its bonding plane is p ', the projection p ' 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

Suppose that the mormal stress of the bonding plane of glue-line unit is σ ', shearing stress is τ ', then

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 is cut than R ' _{σ τ}=σ '/τ ', by itself and drawing to cut and compare R corresponding to n coordinate points on critical broken line _{σ τ}compare, if:

(R _στ) _n-1≤R′ _στ≤(R _στ) _n

Then this glue-line unit (τ ', σ ') is in (n-1)th delta-shaped region, and the line segment on the critical broken line corresponding to this region can 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 bonded adhesives layer unit 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, represent the stress that glue-line unit bears and exceeded ultimate stress, this glue-line unit is in explosive area; If 0≤1-R < is β ₁, the stress margin of safety representing glue-line unit is not enough, and this glue-line unit is in warning area; If β ₁≤ 1-R < β ₂, the stress margin of safety representing glue-line unit is suitable, and this glue-line unit is in place of safety; If β ₂≤ 1-R < 1, the stress margin of safety representing glue-line unit is excessive, and this glue-line unit is in low stress area.β ₁, β ₂value size should be determined by the applying working condition concrete according to bonded structure.

Preferred as one, according to the experience in design of vehicle adhesive, in the present embodiment, get β ₁=20%, β ₂=50%, namely the region of margin of safety 50%≤1-R < 100% that bonded adhesives layer unit is answered is low stress area 8, the region of 20%≤1-R < 50% is place of safety 9, the region of 0≤1-R < 20% is warning area 10, the region of 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 °; With shear stress τ in bonded adhesives layer plane for horizontal ordinate, mormal stress σ is that ordinate sets up coordinate system, experimental data according to form in Fig. 2 described point line in a 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, critical for bonding agent rupture failure broken line graph can be divided into six regions, as shown in Figure 4, drawing corresponding to seven lines is cut and is compared 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＝∞

In order to exemplary illustrated, the window structure that the present invention chooses in EMU checks bonded structure as waiting.Window structure mainly comprises side window glass (12), side window aluminum alloy frame (13) two parts.Window structure, as sub-unit parts, completes assembling by side window aluminum alloy frame (13) with the bonding process of body construction (15), as shown in Figure 6.

According to the main force-bearing situation of 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 the acting force acted on glass for vehicle window that pressure difference inside and outside vehicle window causes, glass unit in the middle part of window structure model applies uniformly distributed load, as shown in Figure 7 (a); In order to simulate window structure bonding with body construction after the remaining shear force that may exist, apply a pair direction opposite effect power in the diagonal of vehicle window, as shown in Figure 7 (b) shows.

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

Can obtain according to shear stress method for solving in described glue-line unit mormal stress and plane:

τ′＝3.60MPa σ′＝3.13MPa

R′ _στ＝σ′/τ′＝0.8694

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

Cut than size contrast (R owing to drawing _{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 that this glue-line unit is positioned at place of safety, the stress state that namely 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 structural adhesive layer unit strength check result as shown in Figure 9.

Above-mentioned is can understand and apply the invention for ease of those skilled in the art to the description of embodiment.Person skilled in the art obviously easily can make various amendment to these embodiments, and General Principle described herein is applied in other embodiments and need not through performing creative labour.Therefore, the invention is not restricted to embodiment here, those skilled in the art, according to announcement of the present invention, do not depart from improvement that scope makes and amendment all should within protection scope of the present invention.

Claims (4)

1. a bonding strength check method for vehicle adhesive, is characterized in that:

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

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

Step 3, change into unit, i.e. glue-line unit by discrete for automobile-used bonding test specimen to be detected, to calculate glue-line unit mormal stress be σ ' and shearing stress is τ ', and 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, represent the stress that glue-line unit bears and exceeded ultimate stress, this glue-line unit is in explosive area; If 0≤1-R < is β ₁, the stress margin of safety representing glue-line unit is not enough, and this glue-line unit is in warning area; If β ₁≤ 1-R < β ₂, the stress margin of safety representing glue-line unit is suitable, and this glue-line unit is in place of safety; If β ₂≤ 1-R < 1, the stress margin of safety representing 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 vehicle adhesive according to claim 1, is characterized in that: according to automobile-used operating mode, described β ₁=20% and β ₂=50%.

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

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