scholarly journals Influence of Pressure and Temperature on the Strength Properties of a Laminate Produced by the RTM Method

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Krzysztof Piernik
Keyword(s):  
Strength Properties ◽  
Technological Parameters ◽  
Polymer Resin ◽  
The Matrix ◽  
Static Tensile ◽  
Flow Through ◽  
Alignment Angle ◽  
Different Dimensions ◽  
Two Parameters ◽  
Glass Mat

Abstract This paper discusses the effect of pressure on the content of microvoids and defects inside laminates fabricated under different pressures, by vacuum methods. Two basic vacuum methods resin transfer molding (RTM) and vacuum bag method were used in this paper. A glass mat with an alignment angle of (0□/90□) and a mass of 450 g/cm2 was used to produce the laminate, and a polymer resin was used as the matrix. Special attention was paid to the technological parameters of both processes. A mathematical analysis of the most important parameters which include flow rate, permeability, and gelation temperature has been carried out. In addition, the resin temperature is used to reduce the viscosity of the resin to facilitate its flow through the reinforcement, and in the final stage of production to control the chemical reactions occurring in the mold. The pressure is chosen so that the resin flow is continuous. The synchronization of these two parameters and the measurement of the time in which they occur are called the “cure cycle”. In the final step of the study, the composite was subjected to a static tensile test, using specimens of two different dimensions (scale effect) to evaluate the effect of microvoids and microcracks created by the processes on the strength of the material.

scholarly journals Evaluation of the Impact of Organic Fillers on Selected Properties of Organosilicon Polymer

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1103
Author(s):  
Sara Sarraj ◽  
Małgorzata Szymiczek ◽  
Tomasz Machoczek ◽  
Maciej Mrówka
Keyword(s):  
Tensile Strength ◽  
Natural Fiber ◽  
Accelerated Aging ◽  
Strength Properties ◽  
Visual Observation ◽  
Walnut Shell ◽  
Pistachio Shell ◽  
Thermoplastic Matrix ◽  
Static Tensile ◽  
The Impact

Eco-friendly composites are proposed to substitute commonly available polymers. Currently, wood–plastic composites and natural fiber-reinforced composites are gaining growing recognition in the industry, being mostly on the thermoplastic matrix. However, little data are available about the possibility of producing biocomposites on a silicone matrix. This study focused on assessing selected organic fillers’ impact (ground coffee waste (GCW), walnut shell (WS), brewers’ spent grains (BSG), pistachio shell (PS), and chestnut (CH)) on the physicochemical and mechanical properties of silicone-based materials. Density, hardness, rebound resilience, and static tensile strength of the obtained composites were tested, as well as the effect of accelerated aging under artificial seawater conditions. The results revealed changes in the material’s properties (minimal density changes, hardness variation, overall decreasing resilience, and decreased tensile strength properties). The aging test revealed certain bioactivities of the obtained composites. The degree of material degradation was assessed on the basis of the strength characteristics and visual observation. The investigation carried out indicated the impact of the filler’s type, chemical composition, and grain size on the obtained materials’ properties and shed light on the possibility of acquiring ecological silicone-based materials.

scholarly journals Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Strength Properties ◽  
Alumina Nanoparticles ◽  
Metal Powders ◽  
Wide Range ◽  
The Matrix ◽  
Spark Plasma ◽  
Average Size

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

The Mechanism of Getting New Composite Polymer Materials with Improved Hardness Properties

2021 ◽  
Vol 887 ◽  
pp. 85-90
Author(s):  
L.S. Elbakyan ◽  
I.V. Zaporotskova ◽  
D.E. Vilkeeva
Keyword(s):  
Carbon Nanotubes ◽  
Polymer Material ◽  
Single Layer ◽  
Scientific Basis ◽  
Strength Properties ◽  
Polymer Materials ◽  
Mechanical Mixing ◽  
Material Component ◽  
Adsorption Interaction ◽  
The Matrix

The main aims and the objectives of the study focused on solving current problems of nanomaterial science of new materials – creating the scientific basis for competitive methods of obtaining and controlling new composite materials having improved strength properties based on carbon-containing polymer matrices with nanotubes stabilized in them. A technology for obtaining experimental samples of nanocompositional polymer material based on polymethylmethacrylate, polybutylmethacrylate, and methacrylic acid doped with carbon nanotubes has been developed, using ultrasonic action and mechanical mixing of the composite mixture to achieve the most uniform distribution of nanotubes in the matrix. To determine the possibility of implementing the mechanism of adsorption interaction of the studied polymer material with the surface of carbon nanotubes, DFT calculations of the interaction of the polymer material component and single-layer carbon nanotubes of various types have been done.

A Novel Coreflood Test to Evaluate EOR Potential of Wettability-Altering Surfactants in Oil-Wet Heterogeneous Carbonate Reservoirs

2021 ◽  
Author(s):  
Yue Shi ◽  
Kishore Mohanty ◽  
Manmath Panda
Keyword(s):  
Oil Recovery ◽  
Carbonate Reservoirs ◽  
Wettability Alteration ◽  
Low Permeability ◽  
High Permeability ◽  
Matrix Permeability ◽  
Rock Heterogeneity ◽  
The Matrix ◽  
Flow Through ◽  
Main Factors

Abstract Oil-wetness and heterogeneity (i.e., existence of low and high permeability regions) are two main factors that result in low oil recovery by waterflood in carbonate reservoirs. The injected water is likely to flow through high permeability regions and bypass the oil in low permeability matrix. In this study, systematic coreflood tests were carried out in both "homogeneous" cores and "heterogeneous" cores. The heterogeneous coreflood test was proposed to model the heterogeneity of carbonate reservoirs, bypassing in low-permeability matrix during waterfloods, and dynamic imbibition of surfactant into the low-permeability matrix. The results of homogeneous coreflood tests showed that both secondary-waterflood and secondary-surfactant flood can achieve high oil recovery (>50%) from relatively homogenous cores. A shut-in phase after the surfactant injection resulted in an additional oil recovery, which suggests enough time should be allowed while using surfactants for wettability alteration. The core with a higher extent of heterogeneity produced lower oil recovery to waterflood in the coreflood tests. Final oil recovery from the matrix depends on matrix permeability as well as the rock heterogeneity. The results of heterogeneous coreflood tests showed that a slow surfactant injection (dynamic imbibition) can significantly improve the oil recovery if the oil-wet reservoir is not well-swept.

scholarly journals Comparison of Vacuum Sintered and Selective Laser Melted Steel AISI 316L

2017 ◽  
Vol 62 (4) ◽  
pp. 2125-2131 ◽  
Author(s):  
Z. Brytan
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Selective Laser Melting ◽  
Strength Properties ◽  
Laser Melting ◽  
Charpy Test ◽  
Steel Type ◽  
Type 316L ◽  
Static Tensile

AbstractThe paper presents the results of the basic mechanical properties determined in the static tensile test, impact un-notched Charpy test and hardness of austenitic stainless steel type 316L produced by two techniques: classical pressing and sintering in a vacuum with rapid cooling and selective laser melting (SLM). In this work fracture surface of Charpy test, samples were studied.The results indicate that application of selective laser melting (SLM) makes it possible to double increase the strength properties of components manufactured from austenitic stainless steel type 316L compared to sintering in a vacuum. Resulted in mechanical properties strongly depend on porosity characteristic and the presence of superficial oxides in the case of sintered steel and the character of observed microstructural defects deriving from non-fully melted powder particles and the formation of voids between subsequently melted pool tracks during the SLM.

scholarly journals ELASTICITY OF SUBSTITUTION AND TECHNICAL PROGRESS: IS THERE A MISSPECIFICATION PROBLEM?

2016 ◽  
Vol 22 (1) ◽  
pp. 101-121 ◽  
Author(s):  
Daniela Federici ◽  
Enrico Saltari
Keyword(s):  
Estimation Procedure ◽  
Elasticity Of Substitution ◽  
Technological Parameters ◽  
Italian Economy ◽  
Spurious Regression ◽  
Long Run ◽  
Correlation Problem ◽  
Short Run ◽  
Modeling Strategy ◽  
Two Parameters

In previous work, we estimated a dynamic model of the Italian economy, showing that its weakness in the past two decades is mainly due to the slowdown in total factor productivity growth. In those models, two parameters play a key role: technological progress and the elasticity of substitution. Recent estimates of those parameters are affected, in our opinion, by a specification problem: technological parameters are inherently long-run but their estimates are based on short-run data. Looking deeply into the estimation procedure, we show that the misspecification issue present in the estimates gives rise to a spurious regression bias (high R2, low DW), because the standard approach does not incorporate frictions and rigidities. Our modeling strategy takes account of them. Although we cannot in general say that our framework gets rid of the serial correlation problem, the statistics for our model do show that residuals are not serially correlated.

scholarly journals RESEARCH OF PHYSICAL AND MECHANICAL PROPERTIES OF WOOD-FIBER MATERIALS

2020 ◽  
pp. 451-457
Author(s):  
Aleksandr Yur'yevich Vititnev ◽  
Yuriy Davydovich Alashkevich ◽  
Natal'ya Geral'dovna Chistova ◽  
Roman Aleksandrovich Marchenko ◽  
Venera Nurullovna Matygullina
Keyword(s):  
Mechanical Properties ◽  
Wood Fiber ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Production Method ◽  
Strength Properties ◽  
Grinding Process ◽  
Technological Parameters ◽  
Fiber Materials ◽  
Traditional Construction

This paper presents the results of experimental studies of the physical and mechanical properties of wood-fiber boards of the wet production method when regulating the design and technological parameters of the grinding process. This allowed us to determine the influence of the working clearance between the grinding discs and the concentration of fibre mass with the subject to of quality change wood fiber after defibrator using the developed construction of the disc fibrillation action on the physico-mechanical properties of boards. As a result of the experiment, regression models were obtained that adequately describe the studied grinding process and allow predicting the values of physical and mechanical properties of the finished product depending on the established  parameters process. A comparative analysis of the size and quality characteristics of the fiber semi-finished product and its fractional composition when using a developed construction the disc of refiner fibrillation action and a traditional design used in industry is carried out. The preferential efficiency of the grinding process under the fibrillating effect the disc of refiner in comparison with the traditional construction disc of refiner is established. As a result, there is a significant improvement in the quality indicators of the fiber semi-finished product and its composition due to the formation and predominance in the total mass of long and thin, respectively, flexible fibrillated fibers with high tile-forming properties, which allows to increase the strength properties of the product (by 20–25%), without using binding resins.

scholarly journals Experimental Study of Rainfall Infiltration in an Analog Fracture-matrix System

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhen Zhong ◽  
Huicai Gao ◽  
Yunjin Hu
Keyword(s):  
Unsaturated Flow ◽  
Rainfall Infiltration ◽  
Combination Method ◽  
Matrix System ◽  
Capillary Barrier ◽  
Hydraulic Behaviour ◽  
Experimental Apparatus ◽  
Matrix Interactions ◽  
The Matrix ◽  
Flow Through

In this study, an experimental apparatus was developed to investigate unsaturated infiltration in an analog fracture-matrix system. Fracture and adjacent matrix is simulated by sands with various particle sizes. Four rainfall infiltration experiments were performed on the analog fracture-matrix system at a constant rainfall rate of 100 mm/h. The process of rainfall infiltration is measured by a combination method of tensiometers and quick moisture apparatus. The measured results reveal that fracture-matrix interactions certainly exert influences on the hydraulic behaviour of unsaturated fractured matrix, and the fluid flow mainly infiltrates along the nonuniform paths within the matrix. Moreover, it is observed that the influences are greater when using a coarser sand to mimic the fracture. Specifically, the wetting phase in the matrix moves faster than that in the fracture; the fracture, therefore, acts as a vertical capillary barrier, but there exists lateral water exchange from the matrix to the fracture. Overall, this study has demonstrated the importance of fracture/matrix interactions, which should be considered when dealing with unsaturated flow through permeable matrices.

scholarly journals To the Question of Designing Baromembrane Combined Type Apparatus

2021 ◽  
Vol 27 (3) ◽  
pp. 415-427
Author(s):  
S. I. Lazarev ◽  
O. V. Lomakina ◽  
V. E. Bulanov ◽  
I. V. Khorokhorina
Keyword(s):  
Strength Properties ◽  
Technological Parameters ◽  
Mechanical Loads ◽  
Membrane Apparatus ◽  
Strength And Stiffness ◽  
Selection Of ◽  
Toroidal Shells ◽  
Type Apparatus

The paper considers works on methods for calculating design and technological parameters, design of membrane equipment, research of technological features of membrane devices, selection of design schemes, methods for calculating strength and stiffness. A method has been developed for calculating mechanical loads and determining the thickness of plates and toroidal shells of a membrane apparatus of the combined type, which makes it possible to assess the strength properties of apparatus of this class. An example of a calculation, which makes it possible to assess the adequacy of the application of this technique to devices of the combined type, is given.

scholarly journals Effects of Knit Stretching and Matrix Crystallinity on the Fatigue Behaviour of Knitted Fabric-Reinforced Gf/Pet Composites

1997 ◽  
Vol 6 (3) ◽  
pp. 096369359700600 ◽  
Author(s):  
E. Moos ◽  
J. Karger-Kocsis
Keyword(s):  
Endurance Limit ◽  
Damage Zone ◽  
Stress Transfer ◽  
Fatigue Behaviour ◽  
Knitted Fabric ◽  
The Matrix ◽  
Static Tensile ◽  
Matrix Morphology ◽  
Number Of Cycles ◽  
Fatigue Endurance

In this study the tension-tension fatigue behaviour of weft-knitted glass fibre fabric-reinforced polyethylene terephthalate (GF/PET) composites was studied as a function of the stretching ratio of the knit The knits were stretched prior to consolidation in wale direction in 0, 25, 50 and 73%, respectively, in order to increase the anisotropy and to alter the mechanical properties of the composites. The influence of the matrix morphology (crystalline, amorphous) on the fatigue response was also investigated by using a composite with unstretched knit reinforcement. The results, displayed in normalized maximum fatigue stress Ms number of cycles (S-N) diagrams showed that the fatigue endurance limit of the GF/PET composites did not depend either on the knit stretching or the matrix crystallinity. The fatigue endurance limit, normalized to the static tensile strength, was found at ≍27 and ≍50 % for the knitted fabric-reinforced composite sheets tested in wale (W) and course (C) direction, respectively. The damage zone seemed to be localized for 1 and 2 rows of loops in C-and W-directions, respectively. This failure mode reflects the stress transfer and redistribution capability of the plain weft-knit reinforcement

Sign in / Sign up

Export Citation Format

Share Document