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Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 92
Author(s):  
Pouya Shojaei ◽  
Riccardo Scazzosi ◽  
Mohamed Trabia ◽  
Brendan O’Toole ◽  
Marco Giglio ◽  
...  

While deposited thin film coatings can help enhance surface characteristics such as hardness and friction, their effective incorporation in product design is restricted by the limited understanding of their mechanical behavior. To address this, an approach combining micro-indentation and meso/micro-scale simulations was proposed. In this approach, micro-indentation testing was conducted on both the coating and the substrate. A meso-scale uniaxial compression finite element model was developed to obtain a material model of the coating. This material model was incorporated within an axisymmetric micro-scale model of the coating to simulate the indentation. The proposed approach was applied to a Ti/SiC metal matrix nanocomposite (MMNC) coating, with a 5% weight of SiC nanoparticles deposited over a Ti-6Al-4V substrate using selective laser melting (SLM). Micro-indentation testing was conducted on both the Ti/SiC MMNC coating and the Ti-6Al-4V substrate. The results of the meso-scale finite element indicated that the MMNC coating can be represented using a bi-linear elastic-plastic material model, which was incorporated within an axisymmetric micro-scale model. Comparison of the experimental and micro-scale model results indicated that the proposed approach was effective in capturing the post-indentation behavior of the Ti/SiC MMNC coating. This methodology can also be used for studying the response of composite coatings with different percentages of reinforcements.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Richard J. G. Löffler ◽  
Martin M. Hanczyc ◽  
Jerzy Gorecki

AbstractIn a recently published paper (doi.org/10.3390/molecules26113116) on self-propelled motion of objects on the water surface, we described a novel surface-active plastic material obtained by dissolution of camphor and polypropylene in camphene at 250 $$^\circ$$ ∘ C. The material has wax-like mechanical properties, can be easily formed to any moldable shape, and allows for longer and more stable self-propelled motion if compared with pure camphor or pure camphene or of a camphene-camphor wax. Here we use scanning electron microscopy to visualize and characterize the microporous structure of the solid polypropylene foam formed in the plastic for different polypropylene contents. The topology of foams remaining in the material after camphor and camphene molecules have been removed through evaporation or dissolution is similar to polypropylene foams obtained using thermally-induced phase separation. We show that the foams have a superhydrophobic surface but strongly absorb non-polar liquids, and suggest an array of potential scientific and industrial applications.


Author(s):  
Shintaro Yoshihara ◽  
hideto YANAGIHARA

Abstract We have developed a method to variably induce lattice strains and to quantitatively evaluate the induced magnetic anisotropy. Both tensile and compressive strains were introduced into epitaxial films of cobalt ferrite (CFO) grown on a single crystal MgO(001) substrate using a four-point bending apparatus made of a plastic material fabricated by a 3D printer. The change in magnetic anisotropy due to bending strain can be measured quantitatively by using the conventional magneto-torque meter. The strain-induced magnetic anisotropy increased with the tensile strain and decreased with the compressive strain as expected from a phenomenological magnetoelastic theory. The magnetoelastic constant obtained from the changes in bending strains shows quantitatively good agreement with that of the CFO films with a uniaxial epitaxial strain. This signifies that the magnetoelastic constant can be evaluated by measuring only one film sample with strains applied by using the bending apparatus.


2022 ◽  
Vol 17 (01) ◽  
pp. C01007
Author(s):  
N. Atanov ◽  
V. Baranov ◽  
L. Borrel ◽  
C. Bloise ◽  
J. Budagov ◽  
...  

Abstract The “muon-to-electron conversion” (Mu2e) experiment at Fermilab will search for the charged lepton flavour violating neutrino-less coherent conversion of a muon into an electron in the field of an aluminum nucleus. The observation of this process would be the unambiguous evidence of the existence of physics beyond the standard model. Mu2e detectors comprise a straw-tracker, an electromagnetic calorimeter and an external veto for cosmic rays. In particular, the calorimeter provides excellent electron identification, a fast calorimetric online trigger, and complementary information to aid pattern recognition and track reconstruction. The detector has been designed as a state-of-the-art crystal calorimeter and employs 1348 pure Cesium Iodide (CsI) crystals readout by UV-extended silicon photosensors and fast front-end and digitization electronics. A design consisting of two identical annular matrices (named “disks”) positioned at the relative distance of 70 cm downstream the aluminum target along the muon beamline satisfies the Mu2e physics requirements. The hostile Mu2e operational conditions, in terms of radiation levels (total expected ionizing dose of 12 krad and a neutron fluence of 5 × 1010 n/cm2 @ 1 MeVeq (Si)/y), magnetic field intensity (1 T) and vacuum level (10−4 Torr) have posed tight constraints on scintillating materials, sensors, electronics and on the design of the detector mechanical structures and material choice. The support structure of each 674 crystal matrix is composed of an aluminum hollow ring and parts made of open-cell vacuum-compatible carbon fiber. The photosensors and front-end electronics for the readout of each crystal are inserted in a machined copper holder and make a unique mechanical unit. The resulting 674 mechanical units are supported by a machined plate of vacuum-compatible plastic material. The plate also integrates the cooling system made of a network of copper lines flowing a low temperature radiation-hard fluid and placed in thermal contact with the copper holders to constitute a low resistance thermal bridge. The data acquisition electronics are hosted in aluminum custom crates positioned on the external lateral surface of the disks. The crates also integrate the electronics cooling system as lines running in parallel to the front-end system. In this paper we report on the calorimeter mechanical structure design, the mechanical and thermal simulations that have determined the design technological choices, and the status of component production, quality assurance tests and plans for assembly at Fermilab.


Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 156
Author(s):  
Victor J. Romero ◽  
Alberto Sanchez-Lite ◽  
Gerard Liraut

The plastic industry is undergoing drastic changes, due to the customer sustainability perception of plastics, and the eruption of new processes (such 3D printing) and materials (such as renewably sourced resins). To enable a fast transition to high-quality, sustainable plastic applications, a specific methodology could be a key competitive advantage. This novel methodology is focused on improving the objectivity and efficiency of plastic production and the design review process. It is applicable to discrete optimization events in any product lifecycle milestone, from concept design to serial production stages. The methodology includes a natural way to capture plastic-related knowledge and trends, oriented towards building a dynamic “interaction matrix”, with a list of potential optimizations and their positive or negative impacts in a comprehensive set of multi-criteria evaluations. With an innovative approach, the matrix allows the possibility to incorporate a business strategy, which could be different at every lifecycle stage. The business strategy is translated from the common “verbal” definition into a quantitative set of “Target and Restrictions”, making it possible to detect and prioritize the best potential design optimization changes according to the strategy. This methodology helps to model and compare design alternatives, verify impacts in every evaluation criteria, and make robust and objective information-based decisions. The application of the methodology in real cases of plastic material design optimization in the automotive industry has provided remarkable results, accelerating the detection of improvement methods aligned with the strategy and maximizing the improvement in product competitiveness and sustainability. In comparison with the simultaneous application of existing mono-criteria optimization methodologies (such as “Design to Cost” or “Eco Design”) and subjective expert-based reviews, the novel methodology has a reduced workload and risks, confirming its potential for future application and further development in other polymer-based products, such as consumer goods or packaging.


2021 ◽  
Vol 37 (6) ◽  
pp. 1434-1439
Author(s):  
J. Morris Princey ◽  
A. Nandhini A. Nandhini ◽  
G. Poojadevi G. Poojadevi ◽  
S. Nobil Divya

Cucurbita pepo and Musa paradisiaca can be considered as a large source of starch which makes it appropriate to be used for the preparation of bio-plastic material. In this study, biodegradable films from Cucurbita pepo and Musa paradisiaca were developed and investigated for their properties like pH, ash, moisture content, amylose content, biodegradability, and antimicrobial activity. 1,2,3-Propanetriol, gingelly oil, and agarose gel was used to reduce the brittleness of the developed starch- based bioplastic films. The investigation of films was done by Spectroscopic and Surface Analysis techniques. The developed bio- films showed substantial properties like less engorgement and insolubility in water which makes it worth a commercial viable product for food packaging.


Author(s):  
Борис Гурьевич Миронов ◽  
Юрий Борисович Миронов

Работа посвящена исследованию кручения неоднородных стержней из идеального жесткопластического материала, находящихся под действием переменного внешнего давления линейно меняющегося вдоль образующей стержня. Определены основные соотношения теории кручения исследуемых стержней. Найдены характеристики основных соотношений и определены соотношения вдоль характеристик. В работе получены интегралы основных соотношений при различных условиях предельного состояния стержня. The work is devoted to the investigation of the torsion of inhomogeneous rods made of ideal hard-plastic material under the action of variable external pressure linearly varying along the generatrix rod. The basic relations of the theory of torsion of the investigated rods. The characteristics of the basic relations are found and relationships along characteristics. The integrals of the basic ratios under different conditions of the limiting state of the bar


Author(s):  
Manish Kumar ◽  
Pronab Roy ◽  
Kallol Khan

The present paper determines collapse moments of pressurized 30°–180° pipe bends incorporated with initial geometric imperfection under out-of-plane bending moment. Extensive finite element analyses are carried out considering material as well as geometric nonlinearity. The twice-elastic-slope method is used to determine collapse moment. The results show that initial imperfection produces significant change in collapse moment for unpressurized pipe bends and pipe bends applied to higher internal pressure. The application of internal pressure produces stiffening effect to pipe bends which increases collapse moment up to a certain limit and with further increase in pressure, collapse moment decreases. The bend angle effect on collapse moment reduces with the increase in internal pressure and bend radius. Based on finite element results, collapse moment equations are formed as a function of the pipe bend geometry parameters, initial geometric imperfection, bend angle, and internal pressure for elastic-perfectly plastic material models.


2021 ◽  
Vol 51 (3) ◽  
pp. 126-129
Author(s):  
Е. F. Kira ◽  
А. A. Bezmenko

It is given in an article the description of the new modification technique for the sling operation with stipulating use of the tubing scrapfrom the front vaginal wall mucosa fixed in an ureterovesical segment zone. This intervention, in our opinion, especially convenient if II type of urine incontinence takes place where dislocation of the invariable urethra is combined with cystocele and there is excess of the vaginal wall, which may be easy used as plastic material. This operation elaborated by authors is performed exclusively by vaginal way, that allows decrease the traumas and complications number, increase the cosmetic effect, simplify the surgical intervention. Recent results of treatment according to this metho dies permit to hope on its efficiency also in days that are more far-off.


Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4332
Author(s):  
Pedro Veiga Rodrigues ◽  
Bruno Ramoa ◽  
Ana Vera Machado ◽  
Philip Cardiff ◽  
João Miguel Nóbrega

Toe caps are one of the most important components in safety footwear, but have a significant contribution to the weight of the shoe. Efforts have been made to replace steel toe caps by polymeric ones, since they are lighter, insulated and insensitive to magnetic fields. Nevertheless, polymeric solutions require larger volumes, which has a negative impact on the shoe’s aesthetics. Therefore, safety footwear manufacturers are pursuing the development of an easy, low-cost and reliable solution to optimize this component. In this work, a solid mechanics toolbox built in the open-source computational library, OpenFOAM®, was used to simulate two laboratory standard tests (15 kN compression and 200 J impact tests). To model the polymeric material behavior, a neo-Hookean hyper-elasto-plastic material law with J2 plastic criteria was employed. A commercially available plastic toe cap was characterized, and the collected data was used for assessment purposes. Close agreements, between experimental and simulated values, were achieved for both tests, with an approximate error of 5.4% and 6.8% for the displacement value in compression and impact test simulations, respectively. The results clearly demonstrate that the employed open-source finite volume computational models offer reliable results and can support the design of toe caps for the R&D footwear industry.


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