Normal force and displacement amplitude influences on silver-plated electrical contacts subjected to fretting wear: A basic friction energy – contact compliance formulation

Abstract

During the last decades, the use of connectors in electrical devices for automotive has significantly increased. This raise in the number of electrical and electronic devices on board has led to a growing number of breakdowns. Indeed, this connectors need to keep a low and stable electrical contact resistance (ECR) but due to engine vibrations, fretting wear damage occur. Characterized by small oscillatory motions, fretting induces wear and oxide debris layer (third body) decaying the electrical contact resistance. The aim of this work is to study the effects of two main factors which are the normal contact force and the displacement amplitude. In this study, a silver-plated contact (2µm of thickness) was investigated applying various loading parameters: 2 N < P < 6 N and ± 3µm < δ* < ± 20 µm. Results show that the ECR endurance decreases when the displacement amplitude increases regardless of the normal force. However, a non-monotonic evolution is found regarding normal force effect. Indeed, for a given displacement amplitude, a rise of the normal force tends to increase the contact pressure but at the same time induces a reduction of the effective sliding amplitude due a larger tangential accommodation. Hence by coupling a friction energy density approach with a basic compliance description, the synergic effect of the normal force and the displacement amplitude is described and the ECR endurance predicted.

Influence of the relative humidity and H2S - SO2 polluted air on the fretting wear behavior of silver-plated electrical contacts

“…Since the first studies realized by Antler [1], [2], the degradation of electrical contacts has been extensively investigated [3][4][5][6][7][8][9][10][11] in order to determine the damage mechanisms and to identify palliative solutions. The most efficient method to reduce fretting wear damage consists in applying noble coatings.…”

The final NO-WEAR state due to dual-mode fretting: Numerical prediction and experimental validation

“…Up to now, the most studies of fretting were focused on the tangential mode [12,13,14,15,16,17], there are very few reports about other fretting modes [18,19,20] and even less about dualmotion fretting [21,22]. The last one occurs by superposition of any two kinds of oscillation modes listed above [20] and includes a plenty of variations of phase portraits within the given degrees of freedom.…”

A review of the effects of cyclic contact loading on fretting fatigue behavior

“…Fretting fatigue has been the subject of numerous investigations over the past few decades, various techniques have been proposed to enhance fretting fatigue life, different methods have been suggested to estimate fretting fatigue life and most of aspects of fretting fatigue mechanism such as crack initiation location, crack propagation direction and fretting fatigue life have been explored. 3–19 However, majority of the previous works have been performed under a constant normal load and fewer investigation have been accomplished on fretting fatigue under variable contact loading. This is while most of engineering applications such as dovetails of turbine blades experience cyclic contact loading.…”