Wedge-test method

The wedge test method is discriminatory and provides a relative ranking for many of the parameters that affect bond-joint durability. 

Brown SR (1982) An evaluation of titanium bonding pretreatments with a wedge test method. In Proceedings of the 27th National SAMPE Symposium. 

Wedge test results suggest that the curing process (e.g., percent crosslinking) of the epoxy-polyamide primer system is not affected by the addition of organosilanes, but may be affected by NTMP. The results of substrate surface characterization, adsorption behavior of applied films, and evaluation of candidate inhibitors by chemical, mechanical, and electrochemical test methods are presented. Mechanisms to explain the observed behavior of the various phosphonate and silane polymer systems are discussed. 

ISO 11343, 1993, Adhesives—Determination of dynamic resistance to cleavage of high strength adhesive bonds under impact conditions- Wedge impact method The method is mainly aimed for the characterisation of metal substrates suitable for automotive applications. An instrumented impact testing machine (pendulum type) of 50-300 J and. 3-5.5ms maximum capacity is required for this test. A blunt wedge of approximately 1 mm tip radius and included angle of 8 is impact driven into a bonded joint at 3 ms" for aluminum alloy adherends and 2 ms" for steel adherends. The impact event should be... 

Use of fracture mechanics test methods for failure analysis of FRP composite elements is feasible, but to the best knowledge of the author, no examples of this have been published. The challenge here is mainly the preparation of suitable test specimens from structural elements and the creation of the starter cracks. ISO 15024 does provide some information on mode I starter crack preparation for nonstandard specimens in an informative appendix (B.8, Guidelines for wedge precracking ), and that procedure can be adapted for other specimen geometries. 

A number of ASTM tests and practices involve durability, but one of the most important is the Wedge Test, ASTM D3762-03. In this method, a wedge is forced into the bond line of a flat-bonded aluminum specimen, thereby creating a tensile stress in the region of the resultant crack tip. The stressed specimen is exposed to an aqueous environment at an elevated temperature, or to any other desired environment. The resultant crack growth with time and failure modes is then evaluated. The test is primarily qualitative, but it is discriminatory in determining variations in adherend surface preparation parameters and adhesive environmental durability. 

ASTM D3762-03 Standard test method for adhesive bonded surface durability of aluminum (wedge test). 

Fracture toughness specimens are sometimes contained in some older capsules, although the types of specimens are not always those recommended by current ASTM test methods. For example, the wedge-open loading (WOL) specimen was used in some early capsules since it is somewhat similar to the compact tensile (CT) specimen, it can be tested in a modified form to generate fracture toughness data. Converting Charpy V-notch... 

The history of airplane corrosion testing includes many successful tests that are now performed routinely, e.g., ASTM G 85 Annex A2 and ASTM G 44. Some other successful tests, such as the wedge test (ASTM D 3762, Test Method for Adhesive-Bonded Surface Durability of Aluminum), discovered as a result of bond line corrosion problems on airplanes, are not described here because they are not strictly corrosion tests. Many of the tests described here are ASTM standards. With others, standardization is being pursued, e.g., electrochemical impedance, or ANCIT (Aluminum-Nitrate Chloride Immersion Test), to replace EXCO [4], Corrosion may never be totally eliminated from an airplane however, further refinements in corrosion testing, made... 

ASTM D 3762-79 (1988) Test Method for Adhesive-Bonded Surface Durability of Aluminium (Wedge Test). 

D-2919. Test Method for Determining Durability of Adhesive Joints Stressed in Shear by Tension Loading. D-3762. Test Method for Adhesive-Bonded Surface Durability of Aluminum (Wedge Test). ... 

Figure 16 Boeing Wedge Test after ASTM Test Method D3762.

ASTM D 3762. (1981). Standard test method for adhesive-bonded surface durability of aluminum (wedge test), Part 22 wood adhesives. American Society for Testing and Materials, West Conshohoken, PA. 

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