A Study of the Average Real Contact Pressure Between Rough Surfaces

It is well known that the friction, wear, fatigue life, and contact resistance (electrical and thermal) are dependent on the contact between the rough profiles of the surfaces. Several different techniques have been used to model this contact (fractal, wavelet, statistical, multiscale, and deterministic methods). Several of these methods have found that the relationship between the real area of contact and load is linear. This suggests that there is a constant contact pressure between two surfaces (the average real contact pressure). Somewhat surprisingly, several works have found that this pressure may be greater than traditional hardness, even when the contact is heavily loaded and the contacts are deforming plastically. This mechanism is often called the asperity persistence. The current work uses a recent multiscale contact model and other theories to explain this mechanism and to help predict the average real contact pressure, especially during heavily loaded contacts.