ASTM D897
Tensile Fixture for Adhesive Bond (Butt Joint) Specimens
ASTM D897 Tensile Fixture – Universal Grip Data Sheet (PDF)
ASTM D897 is the standard test method for tensile properties of adhesive bonds. Two metal adherends are bonded face to face and pulled apart normal to the bond line, so the adhesive is loaded in pure tension rather than in shear or peel. Universal Grip builds a self-aligning tensile fixture whose spherical or universal-joint couplings keep the load on the bond axis, because any bending turns a tensile test into a peel test and lowers the result.
What ASTM D897 Measures
D897 reports the comparative tensile strength of a metal-to-metal adhesive bond: the breaking load divided by the bond area, in MPa or psi, together with the failure mode (cohesive in the adhesive, adhesive at the interface, or a mixture). The standard describes the method as primarily comparative and as a discriminator for surface-preparation and environmental-durability studies, so the value ranks adhesives, pretreatments and cure cycles rather than serving as a design allowable. The adhesive layer is thin, so the result is very sensitive to adherend flatness, alignment and the adhesive thickness.
How the ASTM D897 Test Works
Grind the mating faces of the two adherends flat and parallel, then clean and pretreat them as the adhesive manufacturer directs.
Bond the adherends face to face, control the bondline thickness, and cure under the specified pressure and schedule.
Install the bonded specimen in the fixture holders so the couplings on each side can self-align.
Pull at the loading rate called for in the standard until the bond fails.
Record the maximum load and classify the failure surface.
Calculate tensile strength as load divided by bond area and report the mean, standard deviation and failure modes for the set.
Specimens and Setup
The standard covers metal-to-metal bonds on standard-shape specimens; prepare ten specimens per adhesive.
Flatness and parallelism of the bonded faces matter more than in any shear test; grind, do not just machine.
Keep the bondline thickness consistent across the set and record it.
Condition the cured specimens and test at the same temperature; D897 results change with cure state and moisture.
Check that the fixture couplings move freely before each test so no bending moment reaches the bond.
Universal Grip ASTM D897 Fixture
Self-aligning spherical or universal-joint couplings minimize bending of the bond line
Holders sized to D897-type bonded specimens
Quick specimen installation and removal
Hardened steel, corrosion-resistant construction
50 kN standard capacity; higher capacities on request
Threaded or clevis adapters to suit the load frame
Fits electromechanical and servo-hydraulic universal testing machines
Applications
Structural adhesives
Adhesive comparison and screening
Surface preparation and primer studies
Bonding process QC and durability testing
Related Standards and Products
Send us your specimen dimensions, required capacity and machine connection through our contact page and we will quote an ASTM D897 adhesive tensile fixture. Request a quote
ASTM D897 FAQ
What is the difference between ASTM D897 and D1002?
D897 pulls a bond apart normal to its plane, so the adhesive sees tension. D1002 pulls a single-lap joint along its plane, so the adhesive sees shear. Many adhesives are strong in shear and weak in tension, which is why data sheets quote both.
Why does the fixture need self-aligning couplings?
The bondline is thin and brittle compared with the adherends. If the load path is even slightly off the bond axis, one edge of the bond opens first and the specimen fails in peel at a lower load. Spherical or universal joints let the load find the axis.
How many specimens does D897 call for?
Ten per adhesive. Report the individual values, the mean and the standard deviation, plus the failure mode of each specimen, since a cohesive failure and an interfacial failure at the same load mean different things.
Is D897 strength a design value?
No. The standard describes the method as comparative. Use it to rank adhesives, surface preparations and cure schedules, and to follow environmental durability, not to size real joints.