scholarly journals PROSPECTS OF ANISOGRID LATTICE STRUCTURES USING IN ADAPTERS OF LAUNCH VEHICLE

2019 ◽  
Vol 27 (4) ◽  
pp. 25-34
Author(s):  
Vladislav Arkadiyovych Proroka ◽  
Vladimir Ivanovich Lypovskyi
Keyword(s):  
Numerical Experiment ◽  
Cross Section ◽  
Lattice Structure ◽  
Orthotropic Shell ◽  
Launch Vehicle ◽  
Geometric Parameters ◽  
Carbon Plastic ◽  
Lattice Structures ◽  
Model Calculations ◽  
The Cross

The efficiency of using anisogrid lattice structures in launch vehicle designs, in particular in payload adapters, is investigated. On a specific example of the design of the adapter, which is in operation, it is compared with an anisogrid adapter, which is made of different materials - composite, made by winding, and metal using additive technologies. The performance of the adapter was evaluated by the criterion of minimum mass, subject to the requirements of strength and stability. The initial geometric parameters of the anisogrid lattice structure were determined under the condition that the critical stresses are equal for the symmetric and asymmetric cases of stability loss for the structural orthotropic shell model. Calculations and comparisons were made for composite materials - fiberglass, carbon fiber, organoplastic and boraluminium, as well as metal - AMG6M, BT20. Checking the geometrical parameters calculated on the model of structural orthotropic shell showed that they do not meet the requirements of strength and stability. The choice of geometric parameters of a working adapter design is made by numerical experiment with finite element method. The geometry of the lattice structure of the adapter was parameterized to ensure the variability of two geometric dimensions of the cross section of the longitudinal rib and two geometric dimensions of the cross section of the upper frame. The numerical experiment was performed for the constructions made of carbon plastic and for metals AMG6M, BT20. The results of the calculations showed that the anisogrid lattice structures give a gain on the weight of the adapters, which is up to 50% compared to the designs in operation.

scholarly journals Dynamic Loading of Lattice Structure Made by Selective Laser Melting-Numerical Model with Substitution of Geometrical Imperfections

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2129 ◽  
Author(s):  
Radek Vrána ◽  
Ondřej Červinek ◽  
Pavel Maňas ◽  
Daniel Koutný ◽  
David Paloušek
Keyword(s):  
Mechanical Properties ◽  
Numerical Model ◽  
Cross Section ◽  
Lattice Structure ◽  
Low Velocity Impact ◽  
Lattice Structures ◽  
Laser Melting ◽  
Low Velocity ◽  
Velocity Impact ◽  
Geometrical Imperfections

Selective laser melting (SLM) is an additive technology that allows for the production of precisely designed complex structures for energy absorbing applications from a wide range of metallic materials. Geometrical imperfections of the SLM fabricated lattice structures, which form one of the many thin struts, can lead to a great difference in prediction of their behavior. This article deals with the prediction of lattice structure mechanical properties under dynamic loading using finite element method (FEA) with inclusion of geometrical imperfections of the SLM process. Such properties are necessary to know especially for the application of SLM fabricated lattice structures in automotive or aerospace industries. Four types of specimens from AlSi10Mg alloy powder material were manufactured using SLM for quasi-static mechanical testing and determination of lattice structure mechanical properties for the FEA material model, for optical measurement of geometrical accuracy, and for low-velocity impact testing using the impact tester with a flat indenter. Geometries of struts with elliptical and circular cross-sections were identified and tested using FEA. The results showed that, in the case of elliptical cross-section, a significantly better match was found (2% error in the Fmax) with the low-velocity impact experiments during the whole deformation process compared to the circular cross-section. The FEA numerical model will be used for future testing of geometry changes and its effect on mechanical properties.

scholarly journals Influence of Geometric Parameters on Aerodynamic and Acoustic Performances of Bladeless Fans

2019 ◽  
Author(s):  
Ang Li ◽  
Jun Chen ◽  
Yangfan Liu ◽  
Stuart Bolton ◽  
Patricia Davies
Keyword(s):  
Cross Section ◽  
Fluid Dynamic ◽  
Geometric Parameters ◽  
Design Stage ◽  
Air Velocity ◽  
Cross Sectional ◽  
Future Design ◽  
Cross Sectional Profile ◽  
The Cross ◽  
Sectional Profile

Abstract In recent years, the bladeless fan that does not have visible impellers have been widely applied in household appliances. Since the customers are particularly sensitive to noise and the strength of wind generated by the fan, the aerodynamic and acoustic performances of the fan need to be accurately characterized in the design stage. In this study, computational fluid dynamic (CFD) and computational aeroacoustics (CAA) are applied to investigate the performances of different designs of a bladeless fan model. The influence of four parameters, namely the airfoil selection for cross-section of the wind channel, the slit width, the height of cross-section and the location of the slit, is investigated. The results indicate the streamwise air velocity increases significantly by narrowing the outlet, but the noise level increases simultaneously. In addition, the generated noise increases while the height of fan cross-section increases, and a 4mm height of the cross section is optimal for aerodynamic performance. When the slit is closer to the location of maximum thickness, the performances of the bladeless fan increases. Moreover, the performance is not changed significantly by changing the cross-sectional profile. Finally, the optimal geometric parameters are identified to guide the future design of the bladeless fan.

PECULIARITIES OF NUCLEAR REACTIONS INDUCED BY 6He AND 6Li NUCLEI NEAR THE COULOMB BARRIER

2008 ◽  
Vol 17 (10) ◽  
pp. 2349-2353 ◽  
Author(s):  
YU. E. PENIONZHKEVICH ◽  
R. KALPAKCHIEVA ◽  
A. A. KULKO ◽  
S. M. LUKYANOV ◽  
V. A. MASLOV ◽  
...  
Keyword(s):  
Statistical Model ◽  
Cross Section ◽  
Coulomb Barrier ◽  
Nuclear Reactions ◽  
Transfer Reactions ◽  
Excitation Functions ◽  
Model Calculations ◽  
The Cross ◽  
Evaporation Residues

Excitation functions for evaporation residues in the reactions 206,208 Pb (6,4 He,2n 210 Po , as well as for the transfer reactions in the interaction of 6 He and 6 Li projectiles with Au and Pt were measured at the energies near the Coulomb barrier. Studied reactions were characterized by an increase in the cross-section compared to statistical model calculations.

scholarly journals THE METHODOLOGY AND SOFTWARE FOR CALCULATING THE ERROR OF CYLINDRICAL SURFACE

2019 ◽  
pp. 151-161
Author(s):  
S. Timofeev ◽  
Maxim Lesunov ◽  
A. Hurtasenko ◽  
I. Maslova
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Geometric Parameters ◽  
Shape Error ◽  
Software Module ◽  
Form Errors ◽  
Correct Assignment ◽  
Special Software ◽  
Shape Errors ◽  
The Cross

Various techniques and devices are used to determine the shape errors of large-sized parts of technological units. This is important for the correct assignment of parameters for further reduction processing by special machines and machine tools. The acquired errors arise for several reasons: 1) large dimensions and weight of rotating parts, 2) the instability of the axis of the rotating part mounted on two support rollers, 3) the available initial and acquired shape error in the cross section of the part. It is important to define the types of form errors of the surfaces, error analysis, prediction and calculation of deviations from roundness in the cross section of the bandage, and the evaluation of cylindricity. Modeling of the process of operation and diagnostics of the unit, development of methods for determining errors, calculation of real values of deviations from the original contour on the basis of reconstruction of the contour of the section becomes important and necessary. These processes are performed using modern CAD systems and software. Obtaining data arrays in the process of measurements and their processing with the help of a special software module that performs an interactive calculation of shape errors with different geometric parameters of the cross-section of the bandage, provides the ability to obtain information about the state of the outer surfaces and parts of the supports on the operating unit. This article presents a method for determining the geometric parameters of the shape in the cross section of the rotation part, algorithms and software for reconstructing the contours of the cross sections of the part and calculating the shape error of the outer cylindrical surfaces

scholarly journals Effect of Cross-section Geometry on Air-Demand Ratio in High-head Conduits With Sluice Gate

2021 ◽  
Author(s):  
Alp Bugra Aydin ◽  
Ahmet Baylar ◽  
Fahri Ozkan ◽  
Muhammed Cihat Tuna ◽  
Mualla Ozturk
Keyword(s):  
Froude Number ◽  
Cross Section ◽  
Geometric Parameters ◽  
Hydraulic Radius ◽  
Sluice Gate ◽  
Design Formula ◽  
Gate Opening ◽  
High Head ◽  
The Cross ◽  
Cross Section Geometry

Abstract When the researches on the gated conduits were examined, it was determined that the air-demand ratio changed according to the hydraulic and geometric parameters. However, no study investigated the effect of the cross-section geometry of gated conduits on the air-demand ratio. In this study, the effect of conduit cross-section geometry on the air-demand ratio was examined. Results showed that conduit cross-section geometry was an important effect on the air-demand ratio especially at 10% and 15% gate opening rates. It was seen that the effect of the conduit geometry on the air-demand ratio decreased at 20%, and greater gate opening rates. In addition, a design formula related to the gate opening rate, Froude number, hydraulic radius, and conduit length was presented for estimating the air-demand ratio.

Systematic study of the (n,2n) reaction cross section for 121Sb and 123Sb isotopes

2022 ◽  
Author(s):  
RATANKUMAR SINGH ◽  
N.L. Singh ◽  
Rakesh Chauhan ◽  
Mayur Mehta ◽  
Saraswatula suryanarayan ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Systematic Study ◽  
Reaction Cross Section ◽  
Level Density ◽  
Reaction Cross ◽  
Measured Cross Section ◽  
Model Calculations ◽  
The Cross ◽  
Equilibrium Emission

Abstract The cross sections of the 121Sb(n,2n) 120Sbm and 123Sb(n,2n) 122Sb reactions were measured at 12.50, 15.79 and 18.87 MeV neutron energies relative to the standard 27Al(n,α) 24Na monitor reaction using neutron activation and offline γ-ray spectrometry technique. Irradiations of the samples were performed at the BARC-TIFR Pelletron Linac Facility, Mumbai, India. The quasi-monoenergetic neutron was generated via the 7Li(p,n) reaction. Statistical model calculations were performed by nuclear reaction codes TALYS (ver. 1.9) and EMPIRE (ver. 3.2.2) using various input parameters and nuclear level density models. The cross sections of the ground and the isomeric state as well as the isomeric cross section ratio were studied theoretically from reaction threshold to 26 MeV energies. The effect of pre-equilibrium emission is also discussed in detail using different theoretical models. The present measured cross section were discussed and compared with reported experimental data and evaluation data of the JEFF-3.3, ENDF/B-VIII.0, JENDL/AD-2017 and TENDL-2019 libraries. A detailed analysis of the uncertainties in the measured cross section data was performed using the covariance analysis method. Furthermore, a systematic study of the (n,2n) reaction cross section for 121Sb and 123Sb isotopes were also performed within 14-15 MeV neutron energies using various systematic formulae. This work helps to overcome discrepancies in Sb data and illustrate a better understanding of pre-equilibrium emission in (n,2n) reaction channel.

Generic Geometric Model for 3D Woven Interlock Composites

2011 ◽  
Vol 399-401 ◽  
pp. 478-485 ◽  
Author(s):  
Ansar Mahmood ◽  
Xin Wei Wang ◽  
Chu Wei Zhou
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Cross Section ◽  
Strong Correlation ◽  
Shape Function ◽  
Geometric Model ◽  
Geometric Parameters ◽  
Internal Geometry ◽  
The Cross

The mechanical properties of 3D woven interlock composites (3DWIC) can be tailored via design of their weave architecture. This paper presents a geometric model called Generic Geometric Model (GG-Model) which delineates the weave architecture of 3DWIC based on its realistic internal geometry i.e. geometry of the cross-section and path of tows. In GG-Model, the cross-section of tows has been described through a novel shape function called “Generic Shape Function (GSF)”. The GG-Model uses manufacturer and weaver specified data to calculate geometric parameters of the 3DWIC and the reinforcing fabric. The GG-Model is then validated by comparing modeled parameters with experimental data. Strong correlation is found between modeled parameters and experimental data.

Experimental research on the maximum backwater height in front of a permeable spur dike in the bend of a spillway chute

2019 ◽  
Vol 19 (6) ◽  
pp. 1841-1850 ◽  
Author(s):  
Jinmeng Yang ◽  
Jing Zhang ◽  
Qinghua Zhang ◽  
Xiaomin Teng ◽  
Wei Chen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Regression Analysis ◽  
Cross Section ◽  
Experimental Research ◽  
Water Depth ◽  
Momentum Conservation ◽  
Geometric Parameters ◽  
Spur Dike ◽  
The Cross ◽  
Inflow Discharge

Abstract Hydraulic experiments on installing a permeable spur dike at three positions (1/4, 1/2, and 3/4) on the concave bank of the bend of a spillway chute with three angles (45°, 60° and 75°) were carried out for studying the backwater condition in front of the permeable spur dike. Results show that the maximum backwater height occurs at the cross-section where the permeable spur dike meets the concave bank of the bend. A formula for the maximum backwater height was derived by the employment of the principle of momentum conservation, and the formula indicates that the height is influenced by the geometric parameters of the permeable spur dike and the bend, the layout of the spur dike in the bend, and the inflow discharge. Based on experimental data, a regression analysis was implemented on the water depth coefficient in the formula. Furthermore, the maximum backwater height can be obtained through the water depth at the concave bank of the end of bend when the parameters and installing pattern of the permeable spur dike are determined.

scholarly journals The 55Mn(p,?)56Fe and 55Mn(p,n)55Fe Cross Sections

1983 ◽  
Vol 36 (1) ◽  
pp. 1 ◽  
Author(s):  
LW Mitchell ◽  
DG Sargood
Keyword(s):  
Statistical Model ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Reaction Rates ◽  
Significant Part ◽  
Thermonuclear Reaction ◽  
Model Calculations ◽  
The Cross

The cross section of the reaction 55Mn(p, y)56Pe has been measured in the energy range 0�80-2�04 MeV and of the reaction 55Mn(p, n)55Pe from threshold to 2� 04 MeV. Statistical model calculations reproduce the (p, n) cross section to within a factor of 1� 4, but with the (p, y) reaction they fail by a factor ;;;:2 over a significant part of the energy range. Thermonuclear reaction rates are calculated from the data for temperatures in the range (1-5) x 109 K.

scholarly journals Anisotropy of a Selective Laser-Melted Ti–6Al–4V Lattice Structure

2021 ◽  
Author(s):  
Dingye YAO ◽  
Weixing ZHOU ◽  
Yuli MA ◽  
Bo He
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Cross Sections ◽  
Lattice Structure ◽  
Physical Models ◽  
Image Correlation ◽  
Isotropic Hardening ◽  
Lattice Structures ◽  
Compression Tests ◽  
Small Cross Section

Abstract Selective laser melting (SLM) is a widely adopted additive manufacturing process for the preparation of metallic lattice structures. However, it causes a build-direction-dependent anisotropy of morphologies, microstructures, and mechanical properties, making it difficult to predict the behavior and performance of lattice structures. In this study, tensile samples with different cross-sections and build directions (BDs) were fabricated by SLM. The anisotropic morphology, microstructure, and tensile properties were observed and measured using optical microscopy, scanning electron microscopy, and three-dimensional digital image correlation to determine the effects of the size and BD of SLMed materials. The extracted data were sequentially used to modify the geometric and physical models of the lattice. Body-centered cubic lattice structures were fabricated by SLM, and compression tests were performed to verify the modified compression model. In addition to the BD-related grains, the cross-sectional area of the SLMed sample affects its mechanical properties. The small cross-section makes the microstructure finer because the proportion of the contour path that uses higher power is no longer negligible. The sample with small cross-section has more anisotropy because of the lack of tolerance to heterogeneity and macro defects like roughness. In this study, by analyzing samples with small cross-sections, a model consisting of an isotropic hardening law and Hill’s anisotropic yield function is established to describe the yield and plasticity behavior of the as-built SLMed Ti–6Al–4V lattice. The simulated and experimental data fit very well, verifying the methodology employed in this study.

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