Research Phase of Material Testing
The purpose of material testing is to compare the performance of the adhesives produced from our manufacturing ability to the provided technical data sheets. This allows us to have a more realistic understanding of the strength of the adhesive and the quantity of adhesive spent to bond parts together.
The process of deciding on how to begin material testing is based on the provided properties in the adhesive’s technical data sheet (TDS). Each property, e.g. tensile strength, provided by the manufacturer has been tested using specific standards for material testing which will be described next to each property. It would be very important to then research the standards that the manufacturer has used to test their material so that we can conduct our own material testing that is similar to how their experiments were prepared. Note that it may be difficult to find the information on specific standards because they are publications that are sold online. If your research does not yield any literature results, it is possible to try to find the equivalent of a standard as has been done in this material testing for adhesives. It is also possible to find a generic and well-known method of testing for the property being examined which was also done in this material testing.
In terms of the adhesive, EA E-120HP has been examined to have two properties that were viable for material testing. The first property was the tensile strength (ISO 527-3) for the properties of the cured material. Literature on the testing standard was found, but this test involved manufacturing an adhesive film sample which seemed difficult and irrelevant to our application. The second property was the lap shear strength (ISO 4587) for the performance of the cured material. Literature could not be found on this testing standard and therefore research on an ASTM equivalent (D1002) and generic adhesive overlap shear strength test was found.
Plan for Adhesive Material Testing
The material testing will feature a single lap shear strength test which is a common and economic for testing overlap shear strength. This test is heavily similar to ISO 4587 (used in the TDS) and D1002 (the ASTM equivalent)
Table #1: Material, Curing Process, and Lap Shear Strength given from EA E-120HP Technical Data Sheet
Material | Curing Process | Lap Shear Strength (MPa) |
Aluminum (acid etched) | Cured for 2 hrs @ 65 deg C | 13.7 |
Steel (grit blasted) | Cured for 12 hours @ 65 deg C | 30 |
Aluminum (acid etched & abraded), 0.1 to 0.2 mm gap | 33 | |
Aluminum (anodised) | 14 | |
Stainless steel | 23 | |
Polycarbonate | 6.9 | |
Nylon | 2.3 | |
Wood (Fir) | 11.3 |
Single Lap Shear Test: (D1002, ISO 4587)
Specimen Preparation:
Two rectangular sections that are 25 mm wide, 100 mm long and 1.6 mm thick
An overlap length of 25 mm.
Fixture is used to ensure correct overlap and accurate alignment of the adherend.
Equipment:
Testing can be conducted using standard tension/compression mechanical test equipment
Should ask the university about the use of a universal testing machine (UTM) which is used to test tensile strength and compressive strength of materials.