scholarly journals Numerical method for the prediction of bending properties of glass-epoxy composites

2007 ◽  
pp. 85-95
Author(s):  
Marina Stamenovic ◽  
Slavisa Putic ◽  
Branislav Bajceta ◽  
Dragana Vitkovic
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Numerical Model ◽  
Outer Layer ◽  
Mechanical Test ◽  
Epoxy Composites ◽  
Future Research ◽  
Structural Components ◽  
Bending Properties ◽  
The Relationship

Mechanical properties of composite materials are conditioned by their structure and depend on the characteristics of structural components. In this paper is presented a numerical model by which the bending properties can be predicted on the basis of known mechanical properties of tension and pressure. Determining the relationship between these properties is justified having in mind the mechanics of fracture during bending, where the fracture takes place on the outer layer which is subjected to bending while the break ends on the layer subjected to pressure. The paper gives the values of tension, pressure and bending properties obtained by the corresponding mechanical test. A comparison of the numerical results of bending properties obtained on the basis of the model with the experimental ones, shows their satisfactory agreement. Therefore, this model can be used for some future research to predict bending properties without experiments.

scholarly journals High modulus polyimide particle-reinforcement of epoxy composites

2021 ◽  
Author(s):  
Johannes Essmeister ◽  
M. Josef Taublaender ◽  
Thomas Koch ◽  
D. Alonso Cerrón-Infantes ◽  
Miriam M. Unterlass ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Composite Materials ◽  
Epoxy Matrix ◽  
Epoxy Composites ◽  
High Modulus ◽  
Particle Reinforcement

A novel class of fully organic composite materials with well-balanced mechanical properties and improved thermal stability was developed by incorporating highly crystalline, hydrothermally synthesized polyimide microparticles into an epoxy matrix.

The influence of functionalization time of carbon nanotube on the mechanical properties of the epoxy composites

2017 ◽  
Vol 51 (12) ◽  
pp. 1693-1701 ◽  
Author(s):  
EA Zakharychev ◽  
EN Razov ◽  
Yu D Semchikov ◽  
NS Zakharycheva ◽  
MA Kabina
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Carbon Nanotube ◽  
Composite Materials ◽  
Polymer Composites ◽  
Epoxy Composites ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

This paper investigates the structure, length, and percentage of functional groups of multi-walled carbon nanotubes (CNT) depending on the time taken for functionalization in HNO3 and H2SO4 mixture. The carbon nanotube content and influence of functionalization time on mechanical properties of polymer composite materials based on epoxy matrix are studied. The extreme dependencies of mechanical properties of carbon nanotube functionalization time of polymer composites were established. The rise in tensile strength of obtained composites reaches 102% and elastic modulus reaches 227% as compared to that of unfilled polymer. The composites exhibited best mechanical properties by including carbon nanotube with 0.5 h functionalization time.

Investigation of Mechanical Properties of Silk and Epoxy Composite Materials

2021 ◽  
Vol 889 ◽  
pp. 27-31
Author(s):  
Norie A. Akeel ◽  
Vinod Kumar ◽  
Omar S. Zaroog
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Composite Materials ◽  
Epoxy Composite ◽  
Mechanical Test ◽  
Weight Ratio ◽  
Industrial Applications ◽  
Sem Analysis ◽  
Equivalent Strength ◽  
Test Impact

This research Investigates the new composite materials are fabricated of two or more materials raised. The fibers material from the sources of natural recycled materials provides certain benefits above synthetic strengthening material given that very less cost, equivalent strength, less density, and the slightest discarded difficulties. In the current experiments, silk and fiber-reinforced epoxy composite material is fabricated and the mechanical properties for the composite materials are assessed. New composite materials samples with the dissimilar fiber weight ratio were made utilizing the compression Molding processes with the pressure of 150 pa at a temperature of 80 °C. All samples were exposed to the mechanical test like a tensile test, impact loading, flexural hardness, and microscopy. The performing results are the maximum stress is 33.4MPa, elastic modulus for the new composite material is 1380 MPa, and hardness value is 20.64 Hv for the material resistance to scratch, SEM analysis of the microstructure of new composite materials with different angles of layers that are more strength use in industrial applications.

scholarly journals Mechanical Performance of Unstitched and Silk Fiber-Stitched Woven Kenaf Fiber-Reinforced Epoxy Composites

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4801
Author(s):  
Yasir Khaleel Kirmasha ◽  
Mohaiman J. Sharba ◽  
Zulkiflle Leman ◽  
Mohamed Thariq Hameed Sultan
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Mechanical Test ◽  
Natural Fibers ◽  
Silk Fiber ◽  
Epoxy Composites ◽  
Test Results ◽  
The Impact ◽  
Woven Kenaf

Fiber composites are known to have poor through-thickness mechanical properties due to the absence of a Z-direction binder. This issue is more critical with the use of natural fibers due to their low strength compared to synthetic fibers. Stitching is a through-thickness toughening method that is used to introduce fibers in the Z-direction, which will result in better through-thickness mechanical properties. This research was carried out to determine the mechanical properties of unstitched and silk fiber-stitched woven kenaf-reinforced epoxy composites. The woven kenaf mat was stitched with silk fiber using a commercial sewing machine. The specimens were fabricated using a hand lay-up method. Three specimens were fabricated, one unstitched and two silk-stitched with deferent stitching orientations. The results show that the stitched specimens have comparable in-plane mechanical properties to the unstitched specimens. For the tensile mechanical test, stitched specimens show similar and 17.1% higher tensile strength compared to the unstitched specimens. The flexural mechanical test results show around a 9% decrease in the flexural strength for the stitched specimens. On the other hand, the Izod impact mechanical test results show a significant improvement of 33% for the stitched specimens, which means that stitching has successfully improved the out-of-plane mechanical properties. The outcome of this research indicates that the stitched specimens have better mechanical performance compared to the unstitched specimens and that the decrease in the flexural strength is insignificant in contrast with the remarkable enhancement in the impact strength.

Research Progress on Mechanical Properties of Short Carbon Fibre/Epoxy Composites

2019 ◽  
Vol 12 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Guanghui Zhao ◽  
Jijia Zhong ◽  
Y.X. Zhang
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibre ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Weight Ratio ◽  
Epoxy Composites ◽  
Experimental Techniques ◽  
Research Progress ◽  
Future Research ◽  
Short Carbon

Background: Short carbon fibre reinforced epoxy composites have many advantages such as high strength-to-weight ratio, corrosion resistance, low cost, short fabrication time and easy manufacturing. Researches on the mechanical performance of the composites are mainly carried out by means of experimental techniques and numerical calculation. Objective: The study aims to report the latest progress in the studies of mechanical properties of short carbon fibre reinforced epoxy composites. Methods: Based on recently published patents and journal papers, the experimental studies of short carbon fibre reinforced epoxy composites are reviewed and the effects of short carbon fibre on the mechanical properties of the composites are discussed. Numerical studies using representative volume element in simulating macroscopic mechanical properties of the short fibre reinforced composites are also reviewed. Finally, future research of short carbon fibre reinforced epoxy composites is proposed. Results: Experimental techniques, experimental results and numerical simulating methods are discussed. Conclusion: Mechanical properties of epoxy can be improved by adding short carbon fibres. Fiber surface treatment and matrix modification are effective in enhancing interfacial adhesion between fiber and matrix, and as a result, better mechanical performance is achieved. Compared to the studies on equivalent mechanical properties of the composites, researches on the micro-mechanism of interaction between fiber and matrix are still in infancy due to the complexity of both the internal structure and reinforcing mechanism.

scholarly journals Effects of three-layer structure and age on mechanical properties of moso bamboo

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2406-2415
Author(s):  
Ge Han ◽  
Rongrong Li ◽  
Chuangui Wang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Outer Layer ◽  
Layer Structure ◽  
Moso Bamboo ◽  
Modulus Of Rupture ◽  
Negative Effects ◽  
The Relationship ◽  
Important Basis

The effects of a three-layer structure and age on the mechanical properties of moso bamboo were investigated. The ages of 1-, 3-, and 5-year-old bamboo were chosen to make test samples, and specimens from each age of moso bamboo were divided into three groups (raw bamboo, bamboo removed from outer layer, and bamboo removed from inner layer) for evaluation of modulus of rupture and parallel-to-grain compressive strength. The regression analysis was completed to evaluate the relationship between mechanical properties and bamboo age. The results showed that the age of moso bamboo was positively correlated with the flexural and parallel-to-grain compressive strengths. The mechanical strength of moso bamboo increased with the increased age of moso bamboo. For the moso bamboo with same age, the flexural and parallel-to-grain compressive strengths decreased for the samples without bamboo outer layer. However, for the samples without bamboo inner layer, the parallel-to-grain compressive strength remained unchanged, but the flexural strength increased. The outer layer of bamboo with high toughness and flexibility played an important role during bending. However, the inner layer of bamboo is relatively brittle, which has negative effects on its flexural strength. These results provide an important basis for the bamboo used in engineering.

scholarly journals Mechanical Characterization of Thrombi Retrieved With Endovascular Thrombectomy in Patients With Acute Ischemic Stroke

Stroke ◽  
2021 ◽  
Author(s):  
Nikki Boodt ◽  
Philip R.W. Snouckaert van Schauburg ◽  
Hajo M. Hund ◽  
Behrooz Fereidoonnezhad ◽  
J. Patrick McGarry ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Multivariable Analysis ◽  
Strong Relationship ◽  
Future Research ◽  
Endovascular Thrombectomy ◽  
Mixed Regression ◽  
Human Stroke ◽  
The Relationship

Background and Purpose: Mechanical properties of thromboemboli play an important role in the efficacy of endovascular thrombectomy (EVT) for acute ischemic stroke. However, very limited data on mechanical properties of human stroke thrombi are available. We aimed to mechanically characterize thrombi retrieved with EVT, and to assess the relationship between thrombus composition and thrombus stiffness. Methods: Forty-one thrombi from 19 patients with acute stroke who underwent EVT between July and October 2019 were mechanically analyzed, directly after EVT. We performed unconfined compression experiments and determined tangent modulus at 75% strain (E t75 ) as a measure for thrombus stiffness. Thrombi were histologically analyzed for fibrin/platelets, erythrocytes, leukocytes, and platelets, and we assessed the relationship between histological components and E t75 with univariable and multivariable linear mixed regression. Results: Median E t75 was 560 (interquartile range, 393–1161) kPa. In the multivariable analysis, fibrin/platelets were associated with increased E t75 (aβ, 9 [95% CI, 5 to 13]) kPa, erythrocytes were associated with decreased E t75% (aβ, −9 [95% CI, −5 to −13]) kPa. We found no association between leukocytes and E t75 . High platelet values were strongly associated with increased E t75 (aβ, 56 [95% CI, 38–73]). Conclusions: Fibrin/platelet content of thrombi retrieved with EVT for acute ischemic stroke is strongly associated with increased thrombus stiffness. For thrombi with high platelet values, there was a very strong relationship with thrombus stiffness. Our data provide a basis for future research on the development of next-generation EVT devices tailored to thrombus composition.

scholarly journals Degradation and Damage of Composite Materials in Marine Environment

2020 ◽  
Vol 26 (3) ◽  
pp. 337-342
Author(s):  
Goran VIZENTIN ◽  
Goran VUKELIC
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Marine Environment ◽  
Critical Review ◽  
Numerical Models ◽  
Future Research ◽  
Crucial Step ◽  
Degradation Of Mechanical Properties ◽  
Properties Of Composites ◽  
Environment Influence

IIn spite the fact that composite materials have been in use in the maritime sector for over a half of century, classification societies regulations tend to limit the usage of composites at the larger scale. One of the reasons for such strict class rules is a lack of comprehensive analytical and numerical models representing the behaviour of composites in the sea environment. Understanding the process of degradation and damage of composite materials assisted by sea environment a crucial step in building such a model. This paper aims to give a critical review of the research advancements in assessments of the sea environment influence on the degradation of mechanical properties of composites with a special emphasis on developed models of processes containing water and moisture entering composite inner structure. The list of major references in the last five years is given and suggestions for future research are discussed.

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