Surface Texture Parameters Professor ： R. J. Chang Student ： R. Z. Huang Date ： 2004 / 04 / 14

Surface Texture Parameters Amplitude Parameters Spacing Parameters Hybrid Parameters ADF and BRC Parameters

Roughness Amplitude Parameters Ra Rq Rt 、 Rv 、 Rt Rtm 、 Rvm 、 Rtm Rymax Rz

Ra - Average Roughness Continuous: Discrete:

Ra is Not the End of the Story These three surfaces all have the same Ra, even though the eye immediately distinguishes their different general shapes.

Rq - Root-Mean-Square Roughness Continuous: Discrete: Rq is more sensitive to peaks and valleys

Rt, Rp, and Rv

Rtm, Rpm and Rvm

Rymax (or Rmax) and Rz Rz(DIN), i.e. Rz according to the German DIN standard, is just another name for Rtm in the American nomenclature Rymax (or Rmax) - Maximum Roughness Height Within a Sample Length

Roughness Spacing Parameters Sm - Mean Spacing

Roughness Hybrid Parameters Dq - RMS Average Slope Continuous: Da - Average Absolute Slope Discrete: Continuous:

Statistical Analysis The Amplitude Distribution Function

Rsk -Skewness Continuous: Discrete:

The Bearing Ratio Curve tp as a parameter refers to the bearing ratio at a specified height The bearing ratio curve is the integral (from the top down) of the ADF

Advanced Statistical and Bearing Ratio Analysis Rk is the vertical height between the left and right intercepts of the - line through the ends of the minimum Htp 40% window. This part of the surface is called the "core roughness"

Rk 、 Rpk 、 Rvk 、 MR1 、 MR2 、 A1 and A2 are determined by BRC

Rpk 、 Rvk 、 MR1 and MR2 Rpk Rpk is an estimate of the small peaks above the main plateau of the surface. Rvk Rvk is an estimate of the depth of valleys which will retain lubricant in a functioning part. MR1 MR1 is the fraction of the surface which consists of small peaks above the main plateau. MR2 MR2 is the fraction of the surface which will carry load during the practical lifetime of the part.

A1 and A2 A1 The "area" of the peak portion of the bearing ratio curve is denoted by A1. It is related to Rpk and MR1 A2 The "area" of the valleys in the Rk construction is denoted by A2. It is related to Rvk and MR2:

Reference s.htm#tp%20-%20Bearing%20Ratio ss.htm file.pdf