scholarly journals Effects of Scanning Strategy and Printing Temperature on the Compressive Behaviors of 3D Printed Polyamide-Based Composites

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1783
Author(s):  
Jin Wang ◽  
Jiangyang Xiang ◽  
Hao Lin ◽  
Kui Wang ◽  
Song Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Carbon Fiber ◽  
Yield Strength ◽  
Energy Absorption ◽  
Fiber Reinforcement ◽  
Scanning Strategy ◽  
Fused Deposition ◽  
Pull Out ◽  
Scanning Strategies

In this work, the effects of scanning strategies and printing temperature on mechanical properties and crush behaviors of columns manufactured using the fused deposition modeling (FDM) technique were studied. The results showed that scanning strategy and printing temperature had significant influences on mechanical response and deformation mode of the columns. The columns printed in different scanning strategies showed significant anisotropy due to the preferred orientation of short fibers during the printing process. The columns printed in a circular direction presented the highest compressive force response. The columns printed with carbon fiber-reinforced polyamide in a circular direction showed the final oblique fracture failure mode, in which there were fiber pull-out and matrix pull-apart on fracture surfaces. Different indicators were also used to evaluate the mechanical properties and crushing characteristics of the columns. The carbon fiber reinforcement columns presented the highest energy absorption, and the glass fiber reinforcement columns showed the highest elastic modulus and yield strength. The results indicated that the scanning strategy and printing temperature not only influenced the elastic modulus and yield strength, but also affected the energy absorption performances of the columns.

The equivalent method of double V-wing honeycombs on the in-plane dynamic impact

2021 ◽  
pp. 073168442199086
Author(s):  
Yunfei Qu ◽  
Dian Wang ◽  
Hongye Zhang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Modulus ◽  
Energy Absorption ◽  
Width Ratio ◽  
Size Factor ◽  
Dynamic Impact ◽  
Element Analysis ◽  
Equivalent Method

The double V-wing honeycomb can be applied in many fields because of its lower mass and higher performance. In this study, the volume, in-plane elastic modulus and unit cell area of the double V-wing honeycomb were analytically derived, which became parts of the theoretical basis of the novel equivalent method. Based on mass, plateau load, in-plane elastic modulus, compression strain and energy absorption of the double V-wing honeycomb, a novel equivalent method mapping relationship between the thickness–width ratio and the basic parameters was established. The various size factor of the equivalent honeycomb model was denoted as n and constructed by the explicit finite element analysis method. The mechanical properties and energy absorption performance for equivalent honeycombs were investigated and compared with hexagonal honeycombs under dynamic impact. Numerical results showed a well coincidence for each honeycomb under dynamic impact before 0.009 s. Honeycombs with the same thickness–width ratio had similar mechanical properties and energy absorption characteristics. The equivalent method was verified by theoretical analysis, finite element analysis and experimental testing. Equivalent honeycombs exceeded the initial honeycomb in performance efficiency. Improvement of performance and weight loss reached 173.9% and 13.3% to the initial honeycomb. The double V-wing honeycomb possessed stronger impact resistance and better load-bearing capacity than the hexagonal honeycomb under impact in this study. The equivalent method could be applied to select the optimum honeycomb based on requirements and improve the efficiency of the double V-wing honeycomb.

The Mechanical Properties of Combustion-Sprayed Polymers and Blends

1996 ◽  
Author(s):  
J.A. Brogan ◽  
C.C. Berndt ◽  
A. Claudon ◽  
C. Coddet
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Deposition Temperature ◽  
Processing Parameters ◽  
Low Energy ◽  
Melt Compounding ◽  
Acid Copolymer ◽  
Spray Processing ◽  
Break Water

Abstract The mechanical properties of EMAA copolymer are dependent upon the thermal spray processing parameters. The parameters determine coating temperatures which, in turn, affects the microstructure. If the deposition temperature is too low, (104 °C for PFl 13 and 160 °C for PFl 11) coatings have low strengths and low energy to break values. Increased coating temperatures allow the particles to fully coalesce resulting in maximized strength and elongation to break. However, at 271 °C, PFl 11 had visible porosity which decreased both strength and elastic modulus. Pigment acts as reinforcement in the sense that the modulus increased but the elongation to break decreased, thus reducing the energy to break. Water quenching reduces the elastic modulus and yield strength, but increases the elongation to break for both EMAA formulations. The mechanical properties of post consumer commingled plastic and PCCP / EMMA blends improved if the recycled plastic was pre-processed by melt-compounding. Melt compounding increased the strength and toughness by improving the compatibility among the various polymer constituents. The addition of PCCP increases the modulus and yield strength of ethylene methaciylic acid copolymer.

Ageing Effect on Mechanical Properties of Machined Nanostructures

2013 ◽  
Vol 683 ◽  
pp. 145-149
Author(s):  
Xing Lei Hu ◽  
Ya Zhou Sun ◽  
Ying Chun Liang ◽  
Jia Xuan Chen
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Md Simulation ◽  
Fracture Strain ◽  
Machining Process ◽  
Ageing Process ◽  
Yield Strain ◽  
Before And After ◽  
Mc Simulation

Monte Carlo (MC) method and molecular dynamics (MD) are combined to analyze the influence of ageing on mechanical properties of machined nanostructures. Single crystal copper workpiece is first cut in MD simulation, and then the machined workpiece is used in MC simulation of ageing process, finally the tensile mechanical properties of machined nanostructures before and after ageing are investigated by MD simulation. The results show that machining process and ageing have obvious influence of tensile mechanical properties. After machining, the yield strength, yield strain, fracture strain and elastic modulus reduce by 36.02%, 28.86%, 20.79% and 7.16% respectively. However, the yield strength, yield strain and elastic modulus increase by 4.84%, 1.41% and 1.02% respectively, fracture strain reduce by 24.53% after ageing process. To research the ageing processes of machined nanostructures by MC simulation is both practical and meaningful.

A Study on the Effect of the Temperature on Mechanical Properties of H90 Copper Strip

2019 ◽  
Vol 950 ◽  
pp. 65-69
Author(s):  
Sun Fei ◽  
Xu Cheng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Effect Of Temperature ◽  
Basic Material ◽  
Copper Strip ◽  
Study Results ◽  
Different Temperatures ◽  
Strip Test

In order to study the effect of temperature on the mechanical properties of H90 copper strip material, the H90 copper strip test pieces were heated to different temperatures (20~600 °C) for tensile test; the yield strength, tensile strength, elastic modulus and elongation of H90 copper strip at different temperatures were obtained. Based on the test results, the empirical models of yield strength, tensile strength, elastic modulus of H90 copper strip at high temperature were established; the test showed that, with the increase of temperature, the yield strength, tensile strength and elastic modulus of H90 copper strip decreased greatly, and the elongation after fracture first increased-decreased-increased at 20~600 °C. The study results in this paper provide basic material data for analyzing the effect of temperature on the continuous firing of firearms and other weapons.

Investigation of Pore Structures on Mechanical Properties of Porous Ti by 3D Finite Element Models

2013 ◽  
Vol 647 ◽  
pp. 683-687
Author(s):  
Mi Gong ◽  
Hong Chao Kou ◽  
Yu Song Yang ◽  
Guang Sheng Xu ◽  
Jin Shan Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Finite Element Models ◽  
3D Finite Element ◽  
Pore Model ◽  
Porous Ti ◽  
Pore Structures ◽  
Medium Porosity

The pore structures on mechanical properties of porous Ti were investigated by 3D finite element models. Calculated elastic modulus and yield strength suggested that square-pore models exhibit lower modulus and higher strength compared with another two kinds of shapes (circle and hexagonal). In addition, under the condition of medium porosity (58.96%), integrated property was found in square-pore model which elastic modulus was 26.97GPa, less than 1/3 of hexagonal-pore model; while the yield strength maintained 63.82MPa, doubled the figure of circle-pore model. Thus, models with square-pore structures show potential perspective as hard tissue replacements. Investigation on anisotropy of microstructure implies that the elastic modulus was affected more intensively than the yield strength.

Dependence of Anisotropy of Human Lumbar Vertebral Trabecular Bone on Quantitative Computed Tomography-Based Apparent Density

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Ameet K. Aiyangar ◽  
Juan Vivanco ◽  
Anthony G. Au ◽  
Paul A. Anderson ◽  
Everett L. Smith ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Mechanical Properties ◽  
Finite Element ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Apparent Density ◽  
Transverse Direction ◽  
Quantitative Computed Tomography ◽  
Axial Direction ◽  
Anisotropy Ratio

Most studies investigating human lumbar vertebral trabecular bone (HVTB) mechanical property–density relationships have presented results for the superior–inferior (SI), or “on-axis” direction. Equivalent, directly measured data from mechanical testing in the transverse (TR) direction are sparse and quantitative computed tomography (QCT) density-dependent variations in the anisotropy ratio of HVTB have not been adequately studied. The current study aimed to investigate the dependence of HVTB mechanical anisotropy ratio on QCT density by quantifying the empirical relationships between QCT-based apparent density of HVTB and its apparent compressive mechanical properties— elastic modulus (Eapp), yield strength (σy), and yield strain (εy)—in the SI and TR directions for future clinical QCT-based continuum finite element modeling of HVTB. A total of 51 cylindrical cores (33 axial and 18 transverse) were extracted from four L1 human lumbar cadaveric vertebrae. Intact vertebrae were scanned in a clinical resolution computed tomography (CT) scanner prior to specimen extraction to obtain QCT density, ρCT. Additionally, physically measured apparent density, computed as ash weight over wet, bulk volume, ρapp, showed significant correlation with ρCT [ρCT = 1.0568 × ρapp, r = 0.86]. Specimens were compression tested at room temperature using the Zetos bone loading and bioreactor system. Apparent elastic modulus (Eapp) and yield strength (σy) were linearly related to the ρCT in the axial direction [ESI = 1493.8 × (ρCT), r = 0.77, p < 0.01; σY,SI = 6.9 × (ρCT) − 0.13, r = 0.76, p < 0.01] while a power-law relation provided the best fit in the transverse direction [ETR = 3349.1 × (ρCT)1.94, r = 0.89, p < 0.01; σY,TR = 18.81 × (ρCT)1.83, r = 0.83, p < 0.01]. No significant correlation was found between εy and ρCT in either direction. Eapp and σy in the axial direction were larger compared to the transverse direction by a factor of 3.2 and 2.3, respectively, on average. Furthermore, the degree of anisotropy decreased with increasing density. Comparatively, εy exhibited only a mild, but statistically significant anisotropy: transverse strains were larger than those in the axial direction by 30%, on average. Ability to map apparent mechanical properties in the transverse direction, in addition to the axial direction, from CT-based densitometric measures allows incorporation of transverse properties in finite element models based on clinical CT data, partially offsetting the inability of continuum models to accurately represent trabecular architectural variations.

scholarly journals The effect of rubber on the mechanical properties of epoxy and carbon fiber (Review)

2020 ◽  
Vol 1 (312) ◽  
pp. 11-21
Author(s):  
M. N. Meiirbekov ◽  
◽  
M. B. Ismailov ◽  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Carbon Fiber ◽  
Impact Strength ◽  
Yield Strength ◽  
Strength Properties ◽  
Carboxyl Groups ◽  
Published Data ◽  
Hydroxyl Groups

The paper presents published data on the effect of rubber elastomers on the strength properties of epoxy resin (ES) and carbon fiber. The introduction of 10% rubbers into ES ED-20 leads to an increase in compressive strength by 50%, tensile strength by 51%, impact strength by 133% and elongation by 128%. The optimal content of rubber with carboxyl groups for the OLDEN mixture was 10-12.5%, while the increase in compressive strength was 48%, impact strength - 73% and elongation - 187%. For DER 331 resin, the study was conducted with two hardeners Piperidine and DETA. The best results for Piperidine hardener were obtained on rubber with hydroxyl groups, with its optimal content of 2.5%, impact strength increased by 170%. For the hardener DETA, the best results were obtained on rubber with carboxyl groups at its optimal content of 10%, the increase in impact strength was 66%. When modifying carbon fiber with rubbers, it leads to a significant increase in the yield strength in tension by 42%, the modulus of elasticity in bending by 63%, and with a slight loss of impact strength.

scholarly journals Mechanically Improved and Multifunctional CFRP Enabled by Resins with High Concentrations Epoxy-Functionalized Fluorographene Fillers

2021 ◽  
Author(s):  
Junhua Wei
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Elastic Modulus ◽  
Carbon Fiber ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Reinforcing Particles ◽  
Thermoset Resin ◽  
High Concentrations ◽  
Carbon Based

To meet the maximum potential of the mechanical properties of carbon fiber reinforced plastics (CFRP), stress transfer between the carbon fibers through the polymer matrix must be improved. A recent promising approach reportedly used reinforcing particles as fillers dispersed in the resin. Carbon based fillers are an excellent candidate for such reinforcing particles due to their intrinsically high mechanical properties, structure and chemical nature similar to carbon fiber and high aspect ratio. They have shown great potential in increasing the strength, elastic modulus and other mechanical properties of interest of CFRPs. However, a percolation threshold of ~1% of the carbon-based particle concentration in the base resin has generally been reported, beyond which the mechanical properties deteriorate due to particle agglomeration. As a result, the potential for further increase of the mechanical properties of CFRPs with carbon-based fillers is limited. We report a significant increase in the strength and elastic modulus of CFRPs, achieved with a novel reinforced thermoset resin that contains high loadings of epoxy-reacted fluorographene (ERFG) fillers. We found that the improvement in mechanical performance of CFRPs was correlated with increase in ERFG loading in the resin. Using a novel thermoset resin containing 10 wt% ERFG filler, CFRPs fabricated by wet layup technique with twill weaves showed a 19.6% and 17.7% increase in the elastic modulus and tensile strength respectively. In addition, because of graphene’s high thermal conductivity and high aspect ratio, the novel resin enhanced CFRPs possessed 59.3% higher through-plane thermal conductivity and an 81-fold reduction in the hydrogen permeability. The results of this study demonstrate that high loadings of functionalized particles dispersed in the resin is a viable path towards fabrication of improved, high-performance CFRP parts and systems.

scholarly journals Mechanical characterization of polylactic acid, polycaprolactone and Lay-Fomm 40 parts manufactured by fused deposition modeling, as a function of the printing parameters

2019 ◽  
Vol 16 (2) ◽  
pp. 25-31 ◽  
Author(s):  
Jessica Zuleima Parrado-Agudelo ◽  
Carlos Narváez-Tovar
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Stress ◽  
Fused Deposition Modeling ◽  
Material Selection ◽  
Ultimate Tensile Stress ◽  
Ultimate Stress ◽  
Fused Deposition ◽  
Raster Angle ◽  
Printing Parameters

This study aims to determine the mechanical properties of parts manufactured by Fused Deposition Modeling (FDM) using three biocompatible polymer materials: Polylactic Acid (PLA), Polycaprolactone (PCL) and Lay-Fomm 40. Also, it was analyzed the influence of different printing parameters, material selection, infill percentage, and raster angle, over the mechanical properties. The samples were subjected to tension and compression tests using a universal testing machine, and elastic modulus, yield stress, and ultimate stress were obtained from the stress-strain curves. PLA samples have the highest elastic modulus, yield stress and ultimate stress for both compression and tension tests, for example, the ultimate tensile stress with infill percentage of 30 % and raster angle of 0-90° has an average value of 41.20 MPa, while PCL samples had an ultimate tensile stress average value of 9.68 MPa. On the other hand, Lay-Fomm40 samples had the highest elongations, with percentage values between 300 and 600 %. Finally, ANOVA analysis showed that the choice of the material is the leading printing parameter that contributes to the mechanical properties, with percentages of 84.20% to elastic modulus, 93.30% to yield stress, and 82.44% to ultimate stress. The second important factor is the raster angle, with higher strengths for the 0-90° when compared to 45-135°. On the other hand, the contribution of the infill percentage to the mechanical properties was no statistically significant. The obtained results could be useful for material selection and 3D printing parameters definition for additive manufacturing of scaffolds, implants, and other structures for biomedical and tissue engineering applications.

scholarly journals Continuous Fiber Angle Topology Optimization for Polymer Composite Deposition Additive Manufacturing Applications

Fibers ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 14 ◽  
Author(s):  
Delin Jiang ◽  
Robert Hoglund ◽  
Douglas Smith
Keyword(s):  
Mechanical Properties ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Polymer Composite ◽  
Fiber Reinforcement ◽  
Fiber Direction ◽  
Optimization Approach ◽  
Continuous Fiber ◽  
Fiber Angle

Mechanical properties of parts produced with polymer deposition additive manufacturing (AM) depend on the print bead direction, particularly when short carbon-fiber reinforcement is added to the polymer feedstock. This offers a unique opportunity in the design of these structures since the AM print path can potentially be defined in a direction that takes advantage of the enhanced stiffness gained in the bead and, therefore, fiber direction. This paper presents a topology optimization approach for continuous fiber angle optimization (CFAO), which computes the best layout and orientation of fiber reinforcement for AM structures. Statically loaded structures are designed for minimum compliance where the adjoint variable method is used to compute design derivatives, and a sensitivity filter is employed to reduce the checkerboard effect. The nature of the layer-by-layer approach in AM is given special consideration in the algorithm presented. Examples are provided to demonstrate the applicability of the method in both two and three dimensions. The solution to our two dimensional problem is then printed with a fused filament fabrication (FFF) desktop printer using the material distribution results and a simple infill method which approximates the optimal fiber angle results using a contour-parallel deposition strategy. Mechanical stiffness testing of the printed parts shows improved results as compared to structures designed without accounting for the direction of the composite structure. Results show that the mechanical properties of the final FFF carbon fiber/polymer composite printed parts are greatly influenced by the print direction, and optimized material orientation tends to align with the imposed force direction to minimize the compliance.

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