![]() ![]() ![]() By carefully selecting the shape and size of the piezoelectric component, it is possible to reduce the likelihood of cracking and ensure reliable operation over a longer period. Another approach is to design the device to minimize stress concentrations and distribute the load more evenly across the piezoelectric element. For example, composite materials that combine piezoelectric ceramics with a tough polymer matrix have been shown to have improved mechanical properties and resistance to cracking. One solution to this crack issue is to use a tougher, more durable material for the piezoelectric element. This is a common problem in piezoelectric devices that are subjected to high levels of vibration or shock. When subjected to high or cyclic loads, cracks can form and propagate through the material, eventually leading to failure. Owing to the advantages mentioned above, multilayer piezoelectric ceramic components are widely used in positioning, precise focusing of optical systems, vibration feedback, and sensors, such as deformation & vibration control, health monitoring, high-precision displacement, micro-pumps, medical applications, in and out flow control, fuel injector systems, etc.Piezoelectric ceramics are brittle materials that are sensitive to mechanical stress. Table 1: Properties comparison of single-layer and multi-layer piezoelectric ceramic components Applications Square, disc, ring, rectangular, tubular, etc. ![]() The characteristics are compared in the Table 1 below. Therefore, the displacement of the multilayer actuator is proportional to the applied voltage (V), the number of piezoelectric layers (n), and the d33 (axial) piezoelectric coefficient of the material.Ĭompared with traditional single-layer piezoelectric elements, multi-layer piezo ceramics are smaller in size and can generate greater displacement and output at lower voltages. Δh=(strain per unit field) (electric field) ×(device thickness)=d 33(V/d) (nd)=d 33Vn …………(3) Figure a) shows a schematic diagram of a single-layer element structure, and Figure b) shows a schematic diagram of a multi-layer element structure The principle of the multilayer piezoelectric actuator is to integrate multiple thin-layers of piezoelectric ceramic materials in a parallel manner. The advantages of multilayer actuators include: (1) reproducible displacement at low drive voltages (2) fast response time (sub-microseconds) (3) size miniaturization (4) precision control of displacement. The popularity of multilayer piezoelectric ceramics (PZT) rose rapidly soon after the driving voltage was able to be reduced to below 100V, which was achieved by using precise technology allowing PZT layers to be less than 100 µm thick. Conversely, mechanical stress, or strain, created when an electric field is applied to piezoelectric materials, is used to create “actuators,” that is an application of the inverse piezoelectric effect. These materials are often used as “sensors,” because they generate voltage signals when subjected to mechanical stress or incoming ultrasonic signals. Piezoelectric products are common not only in our day-to-day life, but also in industrial, medical, automotive and national-defense sectors. Since the discovery of piezoelectric phenomenon (conversion of mechanical energy into electrical energy) by Nobel Prize winners Pierre and Jacques Curie in 1880, the application of piezoelectric science has also flourished, and various uses have been developed and practically used in numerous fields. ![]()
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