BS ISO 11003-1:2019 download.Adhesives – Determination of shear
behaviour of structural adhesives.
Adhesives — Determination of shear behaviour of structural adhesives — Part 1:
Torsion test method using butt-bonded hollow cylinders
1 Scope
BS ISO 11003-1 specifies a shear test for the characterization of adhesives In a bond. The shear stress/strain properties of the adhesive (including the shear modulus) are useful for advanced design work, such as in finite element analysLs methods
2 Normative relerences
The following documents are referred to in the text in such a way that some or all ol their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
150 29t Plastics — Standard atmospheres for conditioning and testing
ISO 1036S. AdhesJves — Designauon of main failure patterns
ISO 17212. Structural adhesives — Guidelines for the surface preparation of metals and plastics prior to
adhesive bonding
3 Terms and definitions
No terms and definitions are listed In this document.
ISO and IEC maintain termlnoloØcal databases (or use hi standardization at the Following addresses.
4 PrInciple
The shear deformation of the adhesive in an annular bond between two hollow cylinders, and the corresponding torque, are measured and recorded up to failure of the joint
S Apparatus
S.1 Torsion-testing machine, with a capacity of at least 300 N-rn and preferably of 1 000 N-rn. AIternativei a suitably adapted tensile-testing machine may be used. The machine shall include equipment for recording the torque Instantaneously with an error of less than 1 %. The gripping heads shall be accurately aligned and, If no hydraulic gripping mechanism is available, all bolts and holes shall be precisely machined so that the specimens are mounted En the apparatus and tested free of uncontrolled loads. The machine shall be equipped with an adequately thcrmostatted chamber if tests arc to be carried out at temperatures different from the ambient temperature.
6 Test specimen
6.1 Preparation
6.1.1 Substrate material
Alummium alloy or steel are suitable materials for the adherends. Other materials are acceptable provided the material (including pro-treated surface layers) has a shear modulus at least 10 times higher than that olthe adhesive.
6.1.2 Preparation of the surface
The surfaces to be bonded shall be prepared In accordance with ISO 1721Z or by any method leading to a cohesive lailure within the adhesive layer.
6.1.3 Bonding
Prepare the specimens In accordance with the instructions of the manufacturer of the adhesive. Information about conditioning o(the specimen shall be Included In the test report.
A joint completely filled with adhesive is essential br the reliability of the test. The two adherends shall be bonded coaxiaHy with a maximum Lateral displacement between their two axes of 0.002 r0 (r0 = outer radius), and a maximum angular deviation so that the bond line thkkness varies by no more than 5 % of the recommended thickness. The oining device shall prevent the adhesive from running out of the point and any displacement of the two adherends during curing.
NOTE To achieve this, the two hollow cylinders are aligned with the help of a plug made of polyterafluoroethylene (PTFE) or any other sultble device. A temperature-resistant 0-ring. lnerted Into the PTFE plug and placed Just below the bond, stops the adhesive from running out of the oint. At the other ends of the adherends, two plates fastened to a threaded rod passing through the PTFE plug prevent any dipiacement dunng curing (see Figure 2)
6.1.4 Adhesive bond
The preferred thickness of the bond Is 0,2 mm, For special adhesives, a thickness in the range from 0.05mm to 0.5 mm may be used.
The thickness of the band is defined by a rim which Is machined along the outer perimeter of one adherend. The rim acts as spacer between the two adherends. The adhesive is applied to the machined adherond to fill the space ad)acent to the rim, prior to olning the two adherends. The rim Is removed on the lathe alterthe adhesive is cured (see FigurJ). The resulting adhesive layer shall have a width at least 10 limes its thickness.
6.1.5 Dimensions
Three sizes of specimen (A. B, C) are recommended (see T.ablv.i). although Intermediate sizes are acceptable provided that Isee FotmulaUj):
r10,8r0 (I)
where
is the inner radius of each cylinder; r, Is the outer radius of each cylinder.
6.2 tlumber of specimens
At least five specimens shall be tested for a given adhesive.
7 Test conditions
7.1 Temperature
The temperature of the test shall be one of the standard temperatures specified in 150291. The temperature 01 the specimen shall be measured at the cuter surface of the hollow cylinder, close to the bond (e.g. with thermocouples). Agreement to within ±1 C is required.
7.2 Shear rate
The rate of shear; 7 of the adhesive shall lie within the range from 0,000 S rt to 0,02 s1. NOTE Thcprs*rredrateofshearlso.0l r.
The corresponding rate of anguLar displacement a, to be set on the torsion-testing machine Is given by Formula (2):
r0
where
is the thkkness of the adhesive band, expressed in millimetres.
r is the outer radius at the specimen, expressed in millimetres (see IabiLi).
8 Procedure
Fix the specimens in the test apparatus, equipped with a temperature cabinet if required. Adjust the apparatUS so thiiL the joint is free from any load.
While increasing 11w shear deformation continuously up to the requested maximum value, record the torque-displacement curve. It the specimen fails, check the surfaces of the bonded parts and reject any specimens with incompletely filled adhesive bonds (due e.g. to the presence of bubbles or voids). Sometimes the adhesive layer will not Fall after reaching the maximum shear deformation, especially when loading with a low shear rate. If this happens, repeat the lest with an increasing torque rate until the specimen tails. As before, check the adhesive layer for defects of fabrication. Ensure that cohesive failure is achieved.
9 Calculations
8.1 The shear stress. r, expressed in mcgapascals. in the bond line close to the outer radius is given by Formula (3):
2 Mr
where
N is the torque. expressed In newton milimietres. acting across the )olnt
ro Is he outer radius, expressed In ,nilhme(res. of the cylinders;
is the inner radius expressed in mllhmelre’s, of the cylinders
8.2 The dlspbcement dm measured durtng the test lx composed of the displacement d5 ol the adhesive and the dIsplacement d1 due to the twist ol the two adherends (see FIgure 4). Therefore, the shear strain yin a bond of thickness (is given by Formub t4):
d1 dm’dt,
where d5, d d1 and tare measured in millimetres.
d Is calculated from the shear modulus G1 01 the adherend material and the shear stress acting in the adherends (alternatively, the deformation of the adherends d1 may be determined experimentally at the appropriate temperatures for an unbonded specimen made of the same material and having the same dimensions).
8.3 The shear modulus C5 ( ny) of the adhesive Is determined from the slope of the initial linear portion of the stress-strain curve.
8.4 Calculate the arithmetic mean of the results and the standard deviation for the shear modulus, as well as the highest shear stress (shear strength) and corresponding shear strain and. If applicable, the shear stress and strain at specimen failure.
10 PrecIsion
The precision of this test method Is not known, because interlaboratory data are not available. When lnterlahoratory data are obtained, a precision statement will be added at the following revision.