بررسی عددی و تجربی یک ساختار هیبریدی اگزتیک جدید جهت افزایش برداشت انرژی با استفاده از پیزوالکتریک

In this study, two novel auxetic structures are proposed for vibration-based energy harvesting within low-frequency ranges. Auxetic geometries, characterized by a negative Poisson’s ratio, generate strain in the same direction as the applied stress under mechanical loading, a feature that can be effectively utilized to enhance energy-harvesting efficiency. In the proposed system, a piezoelectric sensor is mounted on an auxetic beam fabricated from polylactic acid (PLA) via additive manufacturing, enabling conversion of the mechanical response into an electrical signal.

Experimental tests were conducted to determine the vibrational and electrical characteristics of the system, and the results were compared and validated against a three-dimensional finite element model (FEM) developed in COMSOL Multiphysics. The performance of the proposed geometries was also evaluated relative to a simple baseline structure (i). Validation results indicated a maximum error of 8.57% in the natural frequency and 2.09% in voltage sensitivity, confirming excellent agreement between the numerical and experimental results. Numerical analyses of three cells under cantilever boundary conditions in the 0–300 Hz range demonstrated the superior performance of the auxetic cell (iii), which achieved a maximum output voltage of 4.61 V at 45 Hz—approximately 4.45% higher than cell (ii) and over 9.7 times greater than cell (i). These findings underscore the high potential of auxetic structures for significantly enhancing the efficiency of vibration-based piezoelectric energy harvesting systems operating in low-frequency ambient environments.