|
|
|
|
Stress-Strain Behaviour
The stress-strain properties of an adhesive can be measured from
bulk samples in tension, shear or compression and from joints
in shear.
The properties are affected by the absorption of atmospheric
moisture resulting in a reduction in the glass transition temperature
(Tg).
For adhesives where Tg is above the operating temperature, moisture
reduces the yield stress, increases ductility and increases creep
rates. |
Stress-strain properties can be used to
define model parameters for input to finite element analysis.
The graph opposite shows how % mass uptake of moisture affects the
stress-strain behaviour of the adhesive, lowering both the Young's
modulus and yield stress.
|
|
| MERL's quasi-static test machines are used
for this testing. Strain is measured using laser extensometry, clip
or strain gauges, or crosshead displacement, depending on the structural
adhesive. MERL's environmental chambers allow the stress-strain response
to be measured under a number of environmental conditions. |
|
|
|
