Ultrasonic Assembly of Biologically Inspired Anisotropic Short Fibre Reinforced Composites

Author(s):  
Richard S. Trask

In nature, both material and structure are formed according to the principles of biologically controlled self-assembly, a process defined as the spontaneous and reversible ordering of small molecular building blocks under the influence of non-covalent, static interactions. The orientation and distribution of reinforcing entities in engineering composites is key to enabling structural efficiency, yet the architecture remains simplistic when compared to the distinctive and unique hierarchies found in Nature. These biological ‘composite’ materials achieve such configurations by accurately controlling the orientation of anisotropic nano- and micro-sized ‘building blocks’, thereby reinforcing the material in specific directions to carry the multidirectional external loads at different length scales. Capturing the design principles underlying the exquisite architecture of such biological materials will overcome many of the mechanical limitations of current engineering composites. The scientific vision for this study is the development of a novel and highly ordered complex architecture fibrous material for additive layer manufacturing. Using novel chemistry and controlled field-effect assembly, functionally graded, stiffness modulated architectures, analogous to those found in nature, are synthesised to realise enhanced mechanical performance, multi-dimensional composite structures. To achieve this, both hierarchical discontinuous fibres (glass fibres with ZnO nanrods) and a new type of ultrasonic device has been developed. The two studies reported here have been successfully employed to manufacture and mechanically characterise the fibres and aligned discontinuous fibres. A 43 % improvement in strength was observed for samples tested parallel to the direction of the fibre reinforcement over those strained normal to the fibre direction, despite the relatively low volume percentage of the reinforcement phase. This technique shows great potential for the low cost instantaneous alignment of structural reinforcement to generate the light-weight high performance structures required for the future.

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2648 ◽  
Author(s):  
Antonio Delle Femine ◽  
Daniele Gallo ◽  
Carmine Landi ◽  
Mario Luiso

The widespread diffusion of Phasor Measurement Units (PMUs) is a becoming a need for the development of the “smartness” of power systems. However, PMU with accuracy compliant to the standard Institute of Electrical and Electronics Engineers (IEEE) C37.118.1-2011 and its amendment IEEE Std C37.118.1a-2014 have typically costs that constitute a brake for their diffusion. Therefore, in this paper, the design of a low-cost implementation of a PMU is presented. The low cost approach is followed in the design of all the building blocks of the PMU. A key feature of the presented approach is that the data acquisition, data processing and data communication are integrated in a single low cost microcontroller. The synchronization is obtained using a simple external Global Positioning System receiver, which does not provide a disciplined clock. The synchronization of sampling frequency, and thus of the measurement, to the Universal Time Coordinated, is obtained by means of a suitable signal processing technique. For this implementation, the Interpolated Discrete Fourier Transform has been used as the synchrophasor estimation algorithm. A thorough metrological characterization of the realized prototype in different test conditions proposed by the standards, using a high performance PMU calibrator, is also shown.


2019 ◽  
Vol 32 (6) ◽  
pp. 662-668
Author(s):  
Xiao-fang Guan ◽  
Cong Liao ◽  
Li Yang ◽  
Guan-jun Chang

The preparation of high-performance polymeric materials with both excellent overall mechanical properties and heat resistance remains a considerable challenge. Inspired by the delicate self-assembly processes in nature, a facile strategy is reported for the preparation of high-performance polymeric materials with enhanced mechanical strength and improved thermal stability. In this instance, we successfully constructed a cation- π cross-linked polyimide (Na-poly(aryl indole) imide (Na-PINI)) film with enhanced mechanical performance and heat resistance (∼490°C). This work presents an innovative design strategy for realizing robust polymeric materials with integrated strength and thermal stability; the cation- π interaction is demonstrated to be a new method that may achieve many useful properties for high-performance polymers.


Author(s):  
Arezki Tagnit-Hamou ◽  
Nancy A. Soliman

This paper presents research work on the development of a green type of ultra-high-performance concrete using ground glass powders with different degrees of fineness (UHPGC). This article presents the development of an innovative, low-cost, and sustainable UHPGC through the use of glass powder to replace cement, and quartz powder particles. An UHPGC with a compressive strength (fc) of up to 220 MPa was prepared and its fresh, and mechanical properties were investigated. The test results indicate that the fresh UHPGC properties were improved when the cement and quartz powder were replaced with non-absorptive glass powder particles. The strength improvement can be attributed to the glass powder’s pozzolanicity and to its mechanical performance (very high strength and elastic modulus of glass). A case study of using this UHPGC is presented through the design and construction of a footbridge. Erection of footbridge at University of Sherbrooke Campus using UHPGC is also presented as a full-scale application.


RSC Advances ◽  
2017 ◽  
Vol 7 (5) ◽  
pp. 2621-2628 ◽  
Author(s):  
Zhenyu Li ◽  
Omid Zabihi ◽  
Jinfeng Wang ◽  
Quanxiang Li ◽  
Jiemin Wang ◽  
...  

Polyacrylonitrile (PAN) reinforced with nano-carbons such as graphene (Gr) and carbon nanotubes (CNTs) provides great opportunity for the development of low-cost and high-performance carbon materials.


2014 ◽  
Vol 564 ◽  
pp. 366-371 ◽  
Author(s):  
M.K.H. Muda ◽  
Faizal Mustapha ◽  
K.D. Mohd Aris ◽  
Mohamed Thariq Hameed Sultan

Laminated structures are assembled so that the fibre orientation provides most of desired mechanical properties and the matrix largely determines the environmental performance. Composites laminate structures are used in a wide range of applications in aerospace, marine, automotive, surface transport and sports equipment markets. Damage to composite components is not always visible to the naked eye and the extent of damage is best determined for structural components by suitable Non Destructive Test (NDT) methods. Alternatively the damaged areas can be located by simply tapping the composite surface and listening to the sound. The damaged areas give a dull response to the tapping, and the boundary between the good and damaged composite can easily be mapped to identify the area for repair. Awareness of and inspection for composite damage should be included in the regular maintenance schedules for composite structures. Particular attention would be made to areas which are more prone to damage. The repair can be done by using composite itself or bio-composite. Bio-composite is a reinforcement of natural fibre such as plant and a material that formed by matrix or resin. Then repairs to aircraft structures are controlled and should be carried out according to the Aircraft Structural Repair Manual (SRM). For other applications the repaired components would normally be expected to meet the original specifications and mechanical performance requirements. This paper presents the fabrication technique including patch repair by using bio-composite which is kenaf and its aim to give a general approach to composite fabrication on patch repair in all applications. Through the described approach, the life of the structure is expanded and met the properties requirements such as low cost, fairly good mechanical properties, high specific strength, non-abrasive, eco-friendly and bio-degradability characteristics.


2021 ◽  
Vol 118 (33) ◽  
pp. e2101296118
Author(s):  
Isabelle Su ◽  
Neosha Narayanan ◽  
Marcos A. Logrono ◽  
Kai Guo ◽  
Ally Bisshop ◽  
...  

Spiders are nature’s engineers that build lightweight and high-performance web architectures often several times their size and with very few supports; however, little is known about web mechanics and geometries throughout construction, especially for three-dimensional (3D) spider webs. In this work, we investigate the structure and mechanics for a Tidarren sisyphoides spider web at varying stages of construction. This is accomplished by imaging, modeling, and simulations throughout the web-building process to capture changes in the natural web geometry and the mechanical properties. We show that the foundation of the web geometry, strength, and functionality is created during the first 2 d of construction, after which the spider reinforces the existing network with limited expansion of the structure within the frame. A better understanding of the biological and mechanical performance of the 3D spider web under construction could inspire sustainable robust and resilient fiber networks, complex materials, structures, scaffolding, and self-assembly strategies for hierarchical structures and inspire additive manufacturing methods such as 3D printing as well as inspire artistic and architectural and engineering applications.


Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2493
Author(s):  
Junlong Yao ◽  
Hanchao Hu ◽  
Zhengguang Sun ◽  
Yucong Wang ◽  
Huabo Huang ◽  
...  

In order to overcome the challenge of synchronously strengthening and toughening polypropylene (PP) with a low-cost and environmental technology, CaCO3 (CC) nanoparticles are modified by tartaric acid (TA), a kind of food-grade complexing agent, and used as nanofillers for the first time. The evaluation of mechanical performance showed that, with 20 wt.% TA-modified CC (TAMCC), the impact toughness and tensile strength of TAMCC/PP were 120% and 14% more than those of neat PP, respectively. Even with 50 wt.% TAMCC, the impact toughness and tensile strength of TAMCC/PP were still superior to those of neat PP, which is attributable to the improved compatibility and dispersion of TAMCC in a PP matrix, and the better fluidity of TAMCC/PP nanocomposite. The strengthening and toughening mechanism of TAMCC for PP involves interfacial debonding between nanofillers and PP, and the decreased crystallinity of PP, but without the formation of β-PP. This article presents a new applicable method to modify CC inorganic fillers with a green modifier and promote their dispersion in PP. The obtained PP nanocomposite simultaneously achieved enhanced mechanical strength and impact toughness even with high content of nanofillers, highlighting bright perspective in high-performance, economical, and eco-friendly polymer-inorganic nanocomposites.


2020 ◽  
Vol 4 (3) ◽  
pp. 84
Author(s):  
Michael Kucher ◽  
Martin Dannemann ◽  
Ansgar Heide ◽  
Anja Winkler ◽  
Niels Modler

Rod-shaped polymer-based composite structures are applied to a wide range of applications in the process engineering, automotive, aviation, aerospace and marine industries. Therefore, the adequate knowledge of manufacturing methods is essential, covering the fabrication of small amounts of specimens as well as the low-cost manufacturing of high quantities of solid rods using continuous manufacturing processes. To assess the different manufacturing methods and compare the resulting quality of the semi-finished products, the cross-sectional and bending properties of rod-shaped structures obtained from a thermoplastic micro-pultrusion process, conventional fibre reinforced epoxy resin-based solid rods and fibre reinforced thermoplastic polymers manufactured by means of an implemented shrink tube consolidation process, were statistically analysed. Using the statistical method one-way analysis of variance (ANOVA), the differences between groups were calculated. The statistical results show that the flexural moduli of carbon fibre reinforced polymers were statistically significantly higher than the modulus of all other investigated specimens (probability value ). The discontinuous shrink tube consolidation process resulted in specimens with a smooth outer contour and a high level of roundness. However, this process was recommended for the manufacturing of small amounts of specimens. In contrast, the pultrusion process allowed the manufacturing of high amounts of semi-finished products; however, it requires a more extensive process controlling and manufacturing equipment.


2021 ◽  
Author(s):  
Alexander Thom ◽  
David Madden ◽  
Rocio Bueno-Perez ◽  
Ali Al Shakhs ◽  
Ciaran Lennon ◽  
...  

To achieve optimal performance in gas storage and delivery applications, metal-organic frameworks (MOFs) must combine high gravimetric and volumetric capacities. One potential route to balancing high pore volume with suitable crystal density is interpenetration, where identical nets sit within the void space of one another. Herein, we report an interpenetrated MIL-53 topology MOF, named GUF-1, where one-dimensional Sc(µ2-OH) chains are connected by 4,4’-(ethyne-1,2-diyl)dibenzoate linkers into a material that is an unusual example of an interpenetrated MOF with a rod-like secondary building unit. A combination of modulated self-assembly and grand canonical Monte Carlo simulations are used to optimise the porosity of GUF-1; H2 adsorption isotherms reveal a very high Qst for H2 of 7.6 kJ mol-1 and a working capacity of 41 g L-1 in a temperature-pressure swing system, which is comparable to benchmark MOFs. These results show that interpenetration is a viable route to high performance gas storage materials comprised of relatively simple building blocks.


2012 ◽  
Vol 2012 (1) ◽  
pp. 000935-000939
Author(s):  
Yiliang Wu ◽  
Ping Liu ◽  
Tony Wigglesworth

Printable conductors with high conductivity would be critical for low-cost printed electronics. In view of printability, conductivity, and electrical stability, metal such as gold or silver derived from solution-deposited precursor compositions would be an ideal candidate. Xerox has been exploring the use of silver nanoparticles as conductor precursor composition for printed electronics. This paper reviews our research in the development of alkylamine-stabilized silver nanoparticles that can be sintered at low temperature (∼ 120 °C) for high conductivity (>10000 S/cm). Silver nanoparticle ink formulations based on these silver nanoparticles exhibit surface-energy independent printability which enables the fabrication of high-performance top-contact transistor devices, and self-assembly characteristic when printed on hydrophilic substrates which allows for large-area, defect-free source drain arrays to be printed with a narrow and uniform channel length.


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