More D However, it does have application as a discriminator in determining variations in adherend surface preparation parameters and adhesive environmental durability. The test method has found applications in controlling surface preparations, primer, and adhesive systems for determining strength properties of tested systems. The apparent shear strength of an adhesive obtained from a given small single-lap specimen may differ from that obtained from a joint made with different adherends or by a different bonding process. The normal variation of temperature and moisture in the service environment causes the adherends and the adhesive to swell or shrink.
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Each test method uses a sample that is bonded together via a single lap shear joint. The standard specifies the following parameters to ensure accurate and consistent testing; The manufacturer of the adhesive will specify the conditions under which the specimen is prepared, unless otherwise agreed upon by the manufacturer and the purchaser.
The manufacturer is required to supply specific information as it relates to the following; Surface preparation procedure Mixing directions for the adhesive being used to bond the samples Detailed adhesive application procedures Thickness, number of coats, rate of spread Detailed test sample assembly conditions Temperature, humidity, etc.
Curing conditions Pressure applied, method of pressure application, etc. Sample conditioning prior to testing Room temperature ranges, humidity ranges, etc. Universal Test Machines are differentiated by capacity and choosing the proper test frame is determined by how much force is required to break the sample, in this case two metal test panels that have been glued together. If you are unsure how much capacity is required for your test, United will perform a free sample test to help you determine system capacity requirements.
You should also discuss capacity requirements with the manufacturer of the adhesive to ensure the system you choose will provide enough capacity to break the samples being tested. United offers Universal Test Machines that range in capacity from our single-column 2.
Dual column frames are available as both table model or floor model systems. The ASTM D standard itself specifies that the test apparatus, grips, and accessories provide the following; Test Frame The testing machine shall conform to the requirements of Practices E4, which all United test frames comply with. Grips A suitable pair of self-aligning grips to hold the specimen. It is recommended that the jaws of these grips shall engage the outer 25 mm 1 in.
Test Specimens Specific test specimen dimensions should be obtained directly from the standard. It is important to note that if your testing procedure results in failure of the metal as opposed to failure of the adhesive a thicker metal sample should be used, or the area over which the adhesive is applied should be modified.
Test Calculations and Reporting The load at failure should be recorded and results should be expressed in kilograms per square centimeter pounds per square inch, PSI of shear area. This is important to note because simply recording the peak force in terms of Newtons, Kilonewtons, or Pound-force is not enough to satisfy the standard. Custom or modified test procedures can also easily be written.
Presentation quality test reports displaying all necessary calculations are available immediately and data is stored a secure and easy to search Access database.
Conclusion United has done virtually all the work for our customers when it comes to performing the ASTM D test procedure. All customers need to do is determine which sample type they will be testing so we can choose the proper test frame capacity and grips.
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ASTM D1002 Adhesive Lap Joint Shear Testing
Nikazahn Even in small specimens, short-term environmental changes asym induce internal stresses or chemical changes in the adhesive that permanently affect the apparent strength and other mechanical properties of the adhesive. Inspection Validating the qstm, value and safety of your raw materials, products and assets. Single-lap tests may be used for comparing and selecting adhesives or bonding processes for susceptibility to fatigue and environmental changes, but such comparisons must be made with great caution since different adhesives may respond differently in different joints. The misuse of strength values obtained from this test method as design-allowable stress values for structural joints could lead to product failure, property damage, and human injury. Validating the specifications, value and safety of s raw materials, products and assets. We offer machines, apparatus, testers, tensile grips, test fixtures, clamps, holders, jigs, faces, jaws, extensometers, environmental and humidity chambers, furnaces, baths and custom solutions for unique applications.
How to Perform an Adhesive Lap Joint Shear Strength Test – ASTM D1002