Model updating and optimum designs for V-shaped atomic force microscope probes

The atomic force microscope (AFM) utilizes a micromachined cantilevered probe with a sharp sensor tip to measure surface topography information and material properties such as Young's modulus. The quality of the measured data is strongly influenced by the modal sensitivity of the AFM probe, which is defined as the change in frequency due to a change in the contact stiffness. A two-stage procedure for the shape optimization of V-shaped AFM probes is proposed. In the first stage, an accurate finite-element (FE) model representing a practical AFM probe is obtained by incorporating experimental frequencies in FE model updating. In the second stage, the updated FE model is used as an initial design and shape optimization is performed to maximize the modal sensitivity for the probe. Examples solved using ANSYS™ finite-element and optimization software demonstrate the effectiveness of the approach.