ASTM D2095 PDF
NLW Adhesive Tensile & Shear Tester. NLW Adhesive Tensile & Shear Tester is professionally applicable to the determination of tensile, shearing, and. D Test Method for Tensile Strength of Adhesives by 1 This practice is under the jurisdiction of ASTM Committee D14 on Adhesives. Purchase your copy of ASTM D – 96() as a PDF download or hard copy directly from the official BSI Shop. All BSI British Standards.
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Transfer of load to an adhesively bonded structure by tension, either directly or indirectly peelrepresents the most severe form of loading, since the strength of the joint relies on the tensile strength of the adhesive, which is low.
It is good design practice, therefore, to ensure that the load is transferred by shear or compression and that direct or induced tensile stresses are minimised. Tensile stresses are virtually impossible to avoid, however there is a need for reliable test methods to measure the tensile properties of the adhesive.
This section examines the tensile butt joint, which is used to evaluate the tensile properties of adhesive joints see also Table 1. Test methods that can be used to measure the static, fatigue and creep behaviour of engineering adhesives, in bulk form, will not be covered in this section. The reader should refer to the ISO standards relating to the testing of polymeric materials [ 12 ]. The cylindrical butt joint can be used to test thin bondlines in tension, torsion and compression.
The average strength is taken as the applied load at failure divided by the bond area.
The test is difficult to perform. Significant bending can be induced due to misalignment of the adherends, resulting in premature ast. Care needs to be taken to ensure good alignment during specimen preparation i.
ASTM D2095 Clevis Grips Adhesive Tensile Tests | GD2095-353
A small misalignment can severely reduce strength data. A further consideration, relates to the removal of the spew fillet i.
The spew is able to transmit some of the applied load, resulting in a significant reduction in the level of axial stresses within the adhesive joint, and thus contributing to the uncertainty in moduli and strength data.
Specimens may be designed with either a circular or square cross-section.
ASTM D Clevis Grips Adhesive Tensile Tests | GD
Circular cross-section asttm are usually used to facilitate manufacture and maintain symmetry. Both circular and square cross-sections, 10 to 50 mm wide, are included within BS EN The adhesive in the bondline is restrained in the radial d0295 circumferential directions by the adherends.
In the absence of this restraint, the adhesive is free to undergo radial contraction with respect to the stiffer adherend. The presence of the adherends has the effect of inducing radial and circumferential stresses, thereby increasing the effective stiffness of the joint. This analysis assumes that the adhesive has a much lower stiffness than the adherends i.
The tensile stresses in the central region of the adhesive layer for butt f2095 specimens are uniformly distributed and there are no shear stresses present [ 6—7 ].
In marked contrast, the stress state in the outer edges is highly complex, varying through the thickness of the adhesive layer. The stress state at the overlap edges i. Large, indefinable, stress concentrations at the periphery of the adhesive layer can be expected to render the strength data meaningless. Rounding the adherend butt edges to a diameter equal to the adhesive thickness can facilitate their removal.
This effectively increases the bondline thickness at the outer edges of the bondline, and as a result non-linear stress effects may result, especially at elevated temperatures and exposure to high humidity environments [ 6—7 ]. It is difficult to envisage using the butt joint for assessing long-term performance of adhesive joints under combined cyclic and hostile environments, considering the difficulties associated with this configuration inc.
Qualitative adhesive property data only Strain measurements difficult High shear and d295 stresses at bondline edges Strength sensitive to spew fillet Sensitive to specimen misalignment Limited to thick and rigid adherends Failure attributed to peel stresses Special bonding fixture required.