A virtual experimental approach to evaluate transverse damage behavior of a unidirectional composite considering noncircular fiber cross-sections

2019 ◽  
Vol 228 ◽  
pp. 111369 ◽  
Author(s):  
Gyu Jeong ◽  
Jae Hyuk Lim ◽  
Chunghyeon Choi ◽  
Sun-Won Kim
Keyword(s):  
Cross Sections ◽  
Experimental Approach ◽  
Unidirectional Composite ◽  
Damage Behavior ◽  
Transverse Damage

Comparison of Low-Velocity Impact Damage Behavior of Unidirectional Carbon Fiber-Reinforced Thermoset and Thermoplastic Composites

2019 ◽  
Vol 809 ◽  
pp. 9-14
Author(s):  
Florian Schimmer ◽  
Sven Ladewig ◽  
Nicole Motsch ◽  
Joachim M. Hausmann ◽  
Ingo Ehrlich
Keyword(s):  
Cross Sections ◽  
Impact Damage ◽  
Test Methods ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Low Velocity ◽  
Damage Behavior ◽  
The Impact

This paper investigates the damage behavior of thermoset and thermoplastic fiber-reinforced composites. The specimens were subjected to low-velocity impacts (LVI) to produce barely visible impact damages (BVID). To compare the dependency of the matrix system and the laminate lay-up on the impact damage, four test series were set up. Therefore, laminates with an epoxy (EP) and a polyether ether ketone (PEEK) matrix in a quasi-isotropic (QI) [+45/0/-45/90]2s and an orthotropic (OT) fiber lay-up [0/90]4s were manufactured. To eliminate the influence of variant fiber systems, the thermoplastic tape and the thermoset prepreg contain similar carbon fibers (CF). After impact testing with three different impact energies, inner damages were investigated by using ultrasonic analyses. To get a deeper understanding of the interior damage mechanisms, cross sections of the damaged areas were examined via reflected light microscopy. By using these destructive and non-destructive test methods, significant differences in the damage behavior of composites with thermoplastic and thermoset matrix systems were identified for both laminate lay-ups.

scholarly journals A comparison of degradation rate bone scaffold morphology between computer simulation and experimental approach

2017 ◽  
Vol 13 (4-2) ◽  
pp. 529-532
Author(s):  
Akbar Teguh Prakoso ◽  
Ardiyansyah Syahrom ◽  
Mohd Ayub Sulong ◽  
Amir Putra Md. Saad ◽  
Irsyadi Yani ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Cross Sections ◽  
Degradation Rate ◽  
Experimental Approach ◽  
Bone Scaffold ◽  
Micro Computed Tomography ◽  
Dynamic Flow ◽  
Porous Magnesium ◽  
Orthopedic Applications ◽  
Good Agreement

The objective of this research is to validate the behavior of degradation rate within porous magnesium scaffolds in terms of morphological which includes weight loss after degradation by means of micro-computed tomography (µCT) based on image processing. The main contribution of this work is finding another method to determine morphology based on computer simulation. In the present study, bone scaffold specimens made of pure magnesium that was prepared with three different percentages of porosities 30%, 41%, and 55%. There were immersed and subjected to the dynamic flow rate of simulated body fluid for periods of 24, 48 and 72 hours. One sample of each specimen was scanned by µCT with a resolution of 17 µm. The cross-sections of raw data were superimposed by using MIMICS software to form a 3D reconstruction of the samples after degradation. The degradation morphology was collected from the simulation and showed good agreement with the experimental results by only less than 2%. Based on the simulation results, it is possible to give a recommendation for the alternative way in the morphological study of orthopedic applications.

Space-time visualization of vibration of a ribbed cylinder

2000 ◽  
Vol 214 (10) ◽  
pp. 1259-1271 ◽  
Author(s):  
J Woodhouse ◽  
J Power
Keyword(s):  
Frequency Analysis ◽  
Cross Sections ◽  
Vibration Analysis ◽  
Experimental Approach ◽  
Space Time ◽  
Theoretical Modelling ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Vibrational Response ◽  
Engineering Vibration

Data from an axial array of sensors along a ribbed cylindrical structure may be analysed to allow the evolving vibrational response to impulsive driving to be plotted as a function of space and time. The process is carried out separately in a series of frequency bands, by first carrying out a time-frequency analysis at each position. Aspects of the behaviour not previously discussed are highlighted by this analysis. These aspects are discussed in the light of a previously published theoretical model [1]. Since reflections from the cylinder's ends also play a role here, it has been necessary to develop further theoretical modelling to interpret the measurements. The new experimental approach, which is described here as the method of ‘space-time cross-sections', has scope for application to other problems involving structure-borne vibration. This illustrates the power of time-frequency analysis and its extensions for engineering vibration analysis.

scholarly journals An experimental and theoretical investigation of flow in a gross pollutant trap

2009 ◽  
Vol 59 (6) ◽  
pp. 1117-1127 ◽  
Author(s):  
J. T. Madhani ◽  
N. A. Kelson ◽  
R. J. Brown
Keyword(s):  
Free Surface ◽  
Cross Sections ◽  
Experimental Approach ◽  
Detailed Comparison ◽  
Cfd Modelling ◽  
Wide Range ◽  
Significant Difference ◽  
Flow Features ◽  
Computational Fluid Dynamics Cfd ◽  
Near Wall

Flow through a gross pollutant trap (GPT) with fully blocked screens is investigated experimentally and theoretically using computational fluid dynamics (CFD). Due to the wide range of possible flow regimes, an experimental approach is developed which uses a downstream weir arrangement to control the nature of the flow and the variation in free surface height. To determine the overall flow structure, measurements are taken at a fixed depth throughout the trap with an Acoustic Doppler Velocimeter (ADV), including velocity profile data across three cross sections of the GPT suitable for more detailed comparison with simulations. Observations of the near-wall flow features at the free surface are also taken, due to their likely importance for understanding litter capture and retention in the GPT. Complementary CFD modelling (using Fluent 6.3) is performed using a two-dimensional k−ɛ turbulence model along with either standard wall law boundary conditions or enhanced near-wall modelling approaches. Comparison with experiments suggest that neither CFD modelling approach could be considered as clearly superior to the other, despite the significant difference in near-wall mesh refinement and modelling that is involved. The experimental approach taken here is found useful to control the flow regime in the GPT and further experiments are recommended to study a greater range of flow conditions.

Multiscale Modeling of Hybrid Composite Structures

2011 ◽  
Vol 471-472 ◽  
pp. 916-921 ◽  
Author(s):  
Milan Růžička ◽  
Jiří Had ◽  
Viktor Kulíšek ◽  
Ondřej Uher
Keyword(s):  
Multiscale Modeling ◽  
Cross Sections ◽  
Composite Structure ◽  
Hybrid Composite ◽  
Composite Structures ◽  
Unidirectional Composite ◽  
Scale Model ◽  
Practical Applications ◽  
Macro Scale ◽  
3D Composite

A novel type of hybrid composite structure has been developed, experimentally investigated and used for many practical applications. The main supporting elements of composite structures are formed by the stamping process of partially cured and axially-oriented carbon fibre rods. This system can fill relatively thick parts of cross sections of beams without risk of delamination. Typical macroscopic sub-cells are formed in the transversal cross section of the part due to this technology. An advantage of this final 3D composite structure is its high shear strength and stiffness in comparison with thick unidirectional composite parts. To absorb the dynamic energy and increase the damping, a rubber-cork layer can be inserted during production, before the final pressing and curing of the whole part. The final stiffness property of the whole 3D composite is obtained from multiscale modeling. It is based on an averaging process and a homogenization technique in FEA. A parametric study was carried out to determine the influence of the size, orientation and thickness of the cell border winding layer on the components of the global elastic material matrix. A comparison of a numerical analysis prediction with experimental results shows acceptable agreement of the elastic modules. A mezzo scale model can be applied for designing a real part on a macro scale.

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

Surface ultrastructure of danazol treated rat endometrium: A SEM study

1983 ◽  
Vol 41 ◽  
pp. 556-557
Author(s):  
R.P. Apkarian ◽  
J.S. Sanfilippo
Keyword(s):  
Cross Sections ◽  
Reproductive Tract ◽  
Preliminary Investigation ◽  
Breast Disease ◽  
Distal Segment ◽  
Uterine Horn ◽  
Female Reproductive Tract ◽  
Ultrastructural Changes ◽  
Cycle Phase ◽  
Sprague Dawley

The synthetic androgen danazol, is an isoxazol derivative of ethisterone. It is utilized in the treatment of endometriosis, fibrocystic breast disease, and has a potential use as a contraceptive. A study was designed to evaluate the ultrastructural changes associated with danazol therapy in a rat model. The preliminary investigation of the distal segment of the rat uterine horn was undertaken as part of a larger study intended to elucidate the effects of danazol on the female reproductive tract.Cross-sections (2-3 mm in length) of the distal segment of the uterine horn from sixteen Sprague-Dawley rats were prepared for SEM. Ten rats in estrus served as controls and six danazol treated rats were noted to have alterations of the estrus cycle i.e. a lag in cycle phase or noncycling patterns. Specimens were fixed in 3% glutaraldehyde in 0.05M phosphate buffer containing CaCl2 at pH 7.0-7.4 and chilled to 4°C. After a brief wash in distilled water, specimens were passed through a graded series of ethanol, critical point dryed in CO2 from absolute ethanol, and coated with 6nm Au. Observations were made with an IS1-40 SEM operated at 15kV.

Sign in / Sign up

Export Citation Format

Share Document