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The flexoelectric effect, which is sensitive to size, refers to the phenomenon of coupling between the strain gradient and electrical polarization and involves higher-order derivatives of physical quantities such as displacement, and the analytical process is complicated and difficult. Therefore, in this paper, a mixed finite element method is developed considering the effects of size effect and flexoelectric effect on the electromechanical coupling behavior of microscale flexoelectric materials. Based on the theoretical model of enthalpy density and the modified couple stress theory, the theoretical model and finite element model of microscale flexoelectric effect are established, and the Lagrange multiplier is used to coordinate the higher-order derivative relationship between the displacement field and its gradient, and the C continuous quadrilateral 8-node (displacement and potential) and 4-node (displacement gradient and Lagrange multipliers) flexoelectric mixed element. By comparing the numerical calculation results and analytical solutions of the electrical output characteristics of the microscale BST/PDMS laminated cantilever structure, it is proved that the mixed finite element method designed in this paper is an effective tool for studying the electromechanical coupling behavior of flexoelectric materials.
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http://dx.doi.org/10.3390/mi14040755 | DOI Listing |
Anal Chim Acta
November 2025
Measurement Technology & Instrumentation Key Laboratory of Hebei Province, Institute of Electrical Engineering, Yanshan University, Qinhuangdao, 066004, China.
Background: With the development of modern agriculture, neonicotinoid pesticides have been widely used due to their high efficiency and strong systemic properties. However, excessive use leads to the accumulation of residues in the food chain, threatening the ecosystem and human health. Pesticide residues are easily accumulated in oilseed crops and become concentrated during the edible oil refining process.
View Article and Find Full Text PDFUltrasonics
September 2025
Paderborn University, Paderborn, Germany.
This study investigates the phenomenon of mode repulsion in Lamb waves propagating through two coupled plates with an elastic interface. Using a spring-based coupling model and the Scaled Boundary Finite Element Method, the dispersion curves of the coupled system are analyzed under various interface conditions-weak coupling, sliding boundary, and perfect coupling. This research highlights how the mechanical stiffness of the interface influences the separation of modes and the emergence of repulsion regions.
View Article and Find Full Text PDFProc Inst Mech Eng H
September 2025
IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
Low back pain is estimated to affect more than 70% of the population. Recently, interspinous posterior devices are gaining attention as a less invasive alternative to the traditional pedicle screw systems. However, since most of these devices are not suitable for the L5-S1 segment, the goals for this study are to design a tailored fixation system for the L5-S1 level and to study its effects on the degenerated spine.
View Article and Find Full Text PDFJ Mech Behav Biomed Mater
September 2025
Medical Technology Lab, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy.
Osteoporosis constitutes a significant global health concern, however the development of novel treatments is challenging due to the limited cost-effectiveness and ethical concerns inherent to placebo-controlled clinical trials. Computational approaches are emerging as alternatives for the development and assessment of biomedical interventions. The aim of this study was to evaluate the ability of an In Silico trial technology (BoneStrength) to predict hip fracture incidence by implementing a novel approach designed to reproduce the phenomenology of falls as reported in clinical data, and by testing its accuracy in three virtual cohorts characterised by different risk profiles.
View Article and Find Full Text PDFComput Methods Biomech Biomed Engin
September 2025
College of Mechanical and Transportation Engineering, Hunan University, Changsha, China.
This article employs a finite element model integrated with the Hybrid III dummy to investigate how automatic braking and active muscle forces influence lower-limb injuries in frontal collisions. Prolonged braking can increase the tibial index, indicating more severe injury to the lower leg. Braking mitigated thigh injury at 50 km/h but exacerbated it at 40 km/h.
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