generally rectangular sections that are 25 mm x 100 mm x 1.6 mm.
Purpose: Fixture for preparing test specimens of similar sizes (25 mm x 100 mm x 1.6 mm)
Criteria:
All three adhesive joints curing at the same time
Can be machined in-house
Testing between:
Steel to steel
Composite to composite
Steel to composite
The idea behind this design is to create a “tray” (Fig. 1) to constrain movement in the outer edges of the specimens. Multiple specimens can be cured at the same time in this tray. The spaces between each individual specimen will be separated with skewers (Fig. 2) as well as the spaces between each adhesive joint on a specimen (Fig. 3). A flat board/weights will be placed on top of all specimens to add pressure.
Fig. 1
Fig. 2
Fig. 3
Figure 4 is an example of how the jig will clamp the test specimen. The green planks are aligned as seen in Figure 3. A flat board should be placed on the ground first and then the specimens should be placed on top of it. Then, a flat board (like a piece of plywood for example) will be placed on top of the specimens and weights will be placed on top of the board to apply downwards pressure on the z axis. There will be four longer boards, two per axis, that run parallel with the sides of the specimens on the x and y axis. These boards are in place so that pipe clamps can apply pressure from the sides. The idea is that the ladder-shaped pieces will ensure that the test pieces line up properly under clamping force. It is possible that more ladder pieces may need to be added in the middle section. Many of these specimens can be lined up at once, basically the limit is the length that the pipe clamp can reach.
Fig. 4
Adhesive Anti-Sticking Solution
Adhesive to be Used: 3M DP 420 and Henkel EA E-120HP (both epoxy adhesives)
For Epoxy:
Parchment Paper
Wax Paper
Polyethylene sheeting (saran wrap)
Mold-release compounds for epoxy
PTFE Tape