PSA D45 1197 Felt - Lap Delamination

The standard “PSA D45 1197 Felt - lap delamination”, developed by the French automobile company Renault, describes a procedure for assessing the adhesion of a material that is likely to delaminate under stress. This procedure applies to felt and lap as well as coated or impregnated materials. It also makes it possible to control the quality of the bond obtained with these materials under well-defined conditions.

Delamination is defined as the separation of the layers that make up a composite. Delamination is a very common type of damage in a composite material consisting of layers due to the low strength between the layers.

In principle, this test determines the load required to separate a sample sandwiched between two parallel plates and subjected to forces perpendicular to the plates and in opposite directions.

Major test equipment used in these tests includes:

• A dynamometer is a device used to measure the force of objects. This device is commonly used to measure the horsepower of a motor or an automobile engine. The product of the torsional force applied to the rotating part and the angular velocity gives the power. A dynamometer must meet the following conditions:
  • Equipment for recording the load-elongation curve
  • Load sensor selected to ensure rupture of the test piece for a load between 5 percent and 95 percent of the maximum scale used
  • 100 mm/min plus/min 10 mm/min movable jaw movement speed
• Metal trays, the features of which are included in the standard annex. Briefly, they are as follows:
  • A surface area of ​​one of its faces is equal to or greater than 100 mm x 100 mm square
  • The other side can be attached to one or the other jaw of the dynamometer.
• The adhesive enables the material to be bonded to metal trays. For example, the neoprene-based adhesive is a double-sided adhesive sheet with a peel strength of at least 51 N/cm measured according to the test method standard D1485 2.
• The conditioned room is a test chamber with a temperature of 23 degrees plus/minus 2 degrees and a relative humidity of 50 percent plus/minus 5 percent.

Samples should be representative of the quantity to be characterized. To ensure this representativeness, it is necessary to know the basic characteristics of the population under study. Sample selection criteria should be specified in the test report, the content of which is defined in standard A10 0156. In case of doubt about sampling, it is necessary to contact the PSA Group to find out the procedure to follow.

The samples are left in the chamber for at least 24 hours, so that air can freely reach both sides. Then five test tubes of 100 mm x 100 mm are taken.

When starting the test, two plates are glued to the surfaces of the test piece with an adhesive according to the instructions. If glue is used, two plates and if necessary both sides of the test piece are glued, the recommended time between gluing and clamping for the adhesive used is waited, the test piece is placed between the two plates, and left to dry in the room for at least 22 hours.

If double-sided adhesive is used, the two plates are first covered with it, then the protective film is peeled off, the material is placed between the two plates and this structure is compressed under a load equal to 50 N.

The two plates are fixed to the jaws of the dynamometer, being extremely careful not to apply any mechanical force to the test piece. The assembly thus produced must be perpendicular to the direction of traction.

Tension is applied until the sample delaminates, the relevant load is noted. The appearance of the separation surface is examined. If separation occurs between the test piece and one of the plates, the result is ignored.

To determine the bond strength, two trays are bonded with the adhesive under test. Optionally, both edges of the test piece are bonded following the instructions in the bonding process. The test piece and the plates are fixed in accordance with the recommendations in the technical sheet of the bonding product or other indications specified in the reference documents. They are left to dry in the room for at least 22 hours or for another period depending on the bonding system used. Dry samples are subjected to the ageing tests, possibly provided for in the reference documents. The two plates are fixed in the jaws of the dynamometer without applying any force to the assembled product. Tension is applied until the plate/material/plate assembly separates. The relevant load is noted.

Among the numerous tests, measurements, analyses and evaluation studies carried out for businesses in various sectors, our organization also provides testing services defined in the “PSA D45 1197 Felt - Wadding Delamination” standard with its trained and expert staff and advanced technological equipment.