The paper presents a new way to conduct passive elimination of vibrations consisting of covering elements of structures with low dynamic stiffness with polylactide (PLA). The PLA cover was created in 3D printing technology. The PLA cover was connected with the structure by means of a press connection. Appropriate arrangement of the PLA cover allows us to significantly increase the dissipation properties of the structure. The paper presents parametric analyses of the influence of the thickness of the cover and its distribution on the increase of the dissipation properties of the structure. Both analyses were carried out using finite element models (FEM). The effectiveness of the proposed method of increasing damping and the accuracy of the developed FEM models was verified by experimental studies. As a result, it has been proven that the developed FEM model of a free-free steel beam covered with polylactide enables the mapping of resonance frequencies at a level not exceeding 0.6% of relative error. Therefore, on its basis, it is possible to determine the parameters of the PLA cover. Comparing a free-free steel beam without cover with its PLA-covered counterpart, a reduction in the amplitude levels of the receptance function was achieved by up to 90%. The solution was validated for a steel frame for which a 37% decrease in the amplitude of the receptance function was obtained.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7254374 | PMC |
http://dx.doi.org/10.3390/ma13092125 | DOI Listing |
Micromachines (Basel)
January 2025
Faculty for the Built Environment, University of Malta, MSD 2080 Msida, Malta.
This paper highlights the optimisation of a key design parameter essential to the development of PMUTs, which are part of the transmitting components of microsensors. These microsensors are designed for use in the Structural Health Monitoring of reinforced concrete structures. Enhancing the effectiveness of the transmitting component allows for greater spacing between microsensors, which in turn reduces the number of devices needed to implement a full structural health monitoring system.
View Article and Find Full Text PDFActa Otolaryngol
January 2025
Department of Otomicrosurgery, Sixth Medical Center of The PLA General Hospital, Beijing, China.
Background: In some rare cases of congenital aplasia of the oval window (OW), malformed facial nerve (FN) locations covering the most or entire OW present a challenge to hearing reconstruction, there is no a highly effective surgical hearing reconstruction methods.
Aims/objectives: To update a Scala tympani drill-out technique (SDT) for abnormal FN course covering the OW.
Material And Methods: All patients of congenital atresia of the OW was recruited between August 2014 and July 2023 in a tertiary-care center.
Trends Biotechnol
January 2025
Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China. Electronic address:
A multitude of plastic-depolymerizing microorganisms and enzymes have been discovered in the plastisphere. Identifying and engineering such microbial strains and enzymes necessitate robust and high-throughput screening strategies for developing effective microbial solutions to counter the plastic accumulation problem and decouple the reliance on fossil resources. This review covers new methods and approaches for the effective high-throughput screening of depolymerizing enzymes for various plastics, such as polyethylene terephthalate (PET), polyurethane (PU), and polylactic acid (PLA).
View Article and Find Full Text PDFBurns
January 2025
Jiangsu Tech-Bio-Med Medical Equipment Co.,Ltd., Changzhou, Jiangsu 213000, China.
Background: Wound closure is the core issue in treating patients with extensive burns. Allogeneic grafts can serve as a suitable temporary substitute in third-degree burns, and the Meek technique has provided encouraging outcomes in recent decades. However, whether allografts and the Meek technique could be used simultaneously so as to leverage the strengths of both has not been extensively examined.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill 27599, United States.
Architecturally hindered crystallization of bottlebrush graft copolymers offers a reaction- and solvent-free pathway for creating injectable elastomers with tissue-mimetic softness. Currently, injectable materials involve solvents and chemical reactions, leading to uncontrolled swelling, leaching of unreacted moieties, and side reactions with tissue. To address this issue, bottlebrush copolymers with a poly(ethylene glycol) (PEG) amorphous block and crystallizable poly(lactic acid) (PLA) grafted chains (A--B) were synthesized, with grafted chains of controlled length arranged along the backbone at controlled spacing.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!