摩擦磨损chapter 4.pdf

4. FRICTION 4. FRICTION 4.1 Introduction 4.1 Introduction Friction is the resistance to motion that exists Friction is the resistance to motion that exists when a solid object is moved tangentially with when a solid object is moved tangentially with respect to the surface of another that it respect to the surface of another that it touches, or when an attempt is made to touches, or when an attempt is made to produce such motion. produce such motion. Economic losses, amounting perhaps to Economic losses, amounting perhaps to 0.5% of the Gross National Product of 0.5% of the Gross National Product of industrialized countries, are incurred industrialized countries, are incurred because we do not know enough about because we do not know enough about minimizing frictional losses during sliding. minimizing frictional losses during sliding. Reduction of friction through improved Reduction of friction through improved design, through the use of more suitable design, through the use of more suitable contacting materials, or through the contacting materials, or through the application of better lubricating substances application of better lubricating substances is an important problem