This experiment is conducted in a freshman-level course: Introduction to Engineering Materials. There are no prerequisites for the course although students should have some knowledge of basic algebra. The objectives are to tension and shear test adhesives and to determine the tensile and shear properties of adhesives. Details of equipment of procedure are given

Stibolt, Kenneth A.

English

NASA Technical Reports Server

N90-24366
TENSILE AND SHEAR STRENGTH OF ADHESIVES
Kenneth A. Stibolt
Anne Arundel Community College
Arnold, Maryland
PREREQUISITES
This experiment is conducted in a freshman-level course:
Introduction to Engineering Materials. There are no pre-
requisites for the course although students should have some
knowledge of basic algebra.
OBJECTIVES
i. To tension and shear test adhesives.
2. To determine the tensile and shear properties of
adhesives.
EQUIPMENT AND SUPPLIES
Tension testing machine.
Flat plate jaws for testing adhesive shear specimens.
Rod jaws for testing adhesive tension specimens.
Adhesive shear specimens.
Adhesive tension specimens.
Vernier calipers.
PROCEDURE
I. Measure dimensions of adhesive contact area for tension
and shear specimens (mm).
2. Calculate contact area of tension and shear specimens
and record results (mm2).
3. Install flat plate jaws in tension testing machine.
4. Mount adhesive shear specimen in flat plate jaws.
5. Slowly increase load on specimen until adhesive fails in
shear. Note and record ultimate load (N).
6. Repeat steps 4 and 5 for the remaining adhesive shear
specimens.
7. Install the rod jaws in tension testing machine.
8. Mount adhesive tension specimen in rod jaws.
9. Slowly increase load on specimen until adhesive fails in
tension. Note and record ultimate load (N).
i0. Repeat steps 8 and 9 for the remaining adhesive tension
specimens.
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RESULTS
I. Calculate ultimate tension and shear stress for all
specimens (Pa).
2. Tabulate adhesive type, load type and ultimate stress.
3. Establish some conclusions about the effectiveness of
the various adhesives tested relative to the material
bonded.
4. Establish some conclusions about the load type (tension
or shear) producing the best adhesive performance.
NOTES TO INSTRUCTORS
This experiment is best conducted on a tension testing
machine with mounting jaws available for testing flat plate
and rod specimens. Figure 1 shows the adhesive tension
specimen. Figure 2 shows the shear specimens. Both are made
from readily available aluminum. Dimensions of the specimens
can be adjusted to the availability of material and load
capacity of the tension testing machine.
Using a variety of adhesives will make the experiment
more interesting. Purchasing types used in the home and in
construction is easy. Obtaining types used for industrial
manufacturing is more difficult. Lead time for bonding
together tension and shear specimens should be long enough
for adhesives to develop their full strength. Try to have
similar surface finishes and clamping pressures for all
specimens.
After the specimens are tested, many can be reused by
removing adhesive and establishing a new substrate. This
can be accomplished by wire brushing, surface grinding or
sanding.
This experiment investigates the effect of load type and
adhesive on ultimate strength. Other test variables can be
introduced such as substrate type (wood and plastic), surface
finish, cure variables and environmental conditions.
116
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Adhesive Tension Specimen
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MATERIAL', ALUMINUM
2 PLATES PER SPECIMEN
OVERLAP PLATES 38 mm FOR SPECIMEN
FIGURE B
Shear Specimen
117



Tensile and shear strength of adhesives

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