http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Mechanical and Biodegradable Properties of Jute/Flax Reinforced PLA Composites
Mohsin Ejaz,Muhammad Muzammil Azad,Atta Ur Rehman Shah,S. Kamran Afaq,Jung-il Song 한국섬유공학회 2020 Fibers and polymers Vol.21 No.11
Green composites possessing biodegradable or recyclable characteristics have gained interest in recent years dueto their ecofriendly, sustainable and lightweight characteristics over the conventional plastic-based materials. In this study,flax and jute natural fibers have been used individually and as hybrid reinforcement into Poly Lactic Acid (PLA) matrix. Thecomposites developed are suitable to be used in biodegradable products in packaging and automobile industries. Hot presscompression molding was used to fabricate samples of PLA/flax, PLA/jute and PLA/flax/jute (hybrid composites). Theconcentration of natural fibers in individual fiber-based composites was varied (between 0-50 %) by weight to investigate itseffect on tensile and impact properties. Maximum tensile properties were obtained for 40 wt% single-fiber reinforced intoPLA. This reinforcement content (40 wt%) was used as reference for hybrid composites. Hybrid composites were fabricatedwith different combinations of jute and flax fibers by keeping the total concentration of reinforcement equal to 40 % byweight. Tensile and Charpy impact tests were performed to evaluate the mechanical properties of the composites. ScanningElectron Microscopy of the tensile fractured surfaces was performed to observe the failure mechanism and adhesion at fibermatrixinterfaces in the composites. Further characterizations included Fourier Transform Infra-Red spectroscopy andBiodegradability tests, which were performed according to ASTM standards. Fourier Transform Infrared analysis revealedinteraction between the natural fibers (jute and flax) and PLA matrix in hybrid composites. The enhanced interaction inhybrid composites resulted in their improved impact resistance. Based on the results obtained in this study, the improvedmechanical and biodegradable properties of these composites make it suitable for use in applications like food-packaging andindoor plastic products in automobiles, to reduce synthetic plastic pollution.
Asif Khan,Muhammad Muzammil Azad,Muhammad Sohail,Heung Soo Kim 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.6
This article reports on the physics-based models for the diagnosis (detection, isolation, localization, and quantification of damages) and prognosis (prediction of the future evolution of damages) of laminated composites. The model-based and data-driven prognostic strategies are compared, followed by a summary of the most common failure modes and the failure mechanisms of laminated composite materials. Then, an overview is provided of the measurement-based empirical/phenomenological and finite element-based damage evolution models for composite materials. The techniques reviewed in the former are Paris’s law and its modified versions, stiffness degradation models, Bayesian framework (Particle filters, Bayesian inference, dynamic Bayesian networks), and minimum strain energy theory. The finite element-based models overviewed failure criteria (Hashin, Puck, stress failure criteria) and damage propagation criteria (B-K criterion, equivalent strain/displacement criterion, strain rate-dependent damage model, cohesive zone modeling, De-Cohesive Law). Due to their complex failure modes, there is no generalized global solution for the diagnostics and prognostics of composite materials. The article will serve as guidelines for the physics-based prognostics and health management (PHM) of composite materials.