The effects of stress state, loading frequency and cyclic waveforms on the fatigue behavior of silver-filled electronically-conductive adhesive joints

Abstract

Conductive adhesives and filled adhesive systems, in general, are used in a variety of engineering applications. There are a number of issues of concern in the design of joints bonded using electronically conductive adhesives (ECAs) and subjected to cyclic loading. These include the effects of stress state and cyclic parameters (frequency and waveform) of mechanical and/or thermal loading on the fatigue failure behavior of adhesively-bonded joints. In order to study the effects of these parameters on joint behavior, two different joint geometries were designed and tested under a spectrum of fatigue and environmental conditions. The results of our work indicated a profound influence of the stress state and cyclic waveform type on the fatigue strength of the joints. Lowering the cyclic load frequency was also found to reduce the fatigue life of the bonded joints.

Keywords:

• ELECTRONICALLY CONDUCTIVE ADHESIVES
• FATIGUE
• ELEVATED TEMPERATURE
• ELEVATED HUMIDITY
• CYCLIC LOADING
• STRESS STATE
• CYCLIC FREQUENCY
• WAVEFORM
• FRACTURE
• ENDURANCE LIMIT
• P-N CURVE
• CYCLIC CREEP
• RATE EFFECT
• MODE-I
• MODE-III
• CRACK GROWTH