Characterization of Micro-Crack Orientation in a Thin Plate Using Quasi-Static Component Generated by Incident Ultrasonic Lamb Waves.

The directivity of the quasi-static component (QSC) is quantitatively investigated for evaluating the orientation of a micro-crack buried in a thin solid plate using the numerical simulation method. Based on the bilinear stress-strain constitutive model, a three-dimensional (3D) finite element model (FEM) is built for investigating the nonlinear interaction between primary Lamb waves and the micro-crack. When the primary Lamb waves at A0 mode impinge on the micro-crack, under the modulation of the contact acoustic nonlinearity (CAN), the micro-crack itself will induce QSC.

Laser patterned graphene pressure sensor with adjustable sensitivity in an ultrawide response range.

Flexible pressure sensors have attracted wide attention because of their applications in wearable electronic, human-computer interface, and healthcare. However, it is still a challenge to design a pressure sensor with adjustable sensitivity in an ultrawide response range to satisfy the requirements of different application scenarios. Here, a laser patterned graphene pressure sensor (LPGPS) is proposed with adjustable sensitivity in an ultrawide response range based on the pre-stretched kirigami structure.

The Mechanical Effect of MnO Layers on Electrochemical Actuation Performance of Nanoporous Gold.

This study investigated the electrochemical actuation behavior of nanoporous material during the capacitive process. The length change of nanoporous gold (npg) was in situ investigated in a liquid environment using the dilatometry technique. The mechanical effect of MnO layers was introduced in this work to improve the actuation characteristics of the npg samples.