scholarly journals An Analytical Model for the Uniaxial Tensile Modulus of Plain-Woven Fabric Composites and Its Application and Experimental Validation

Aerospace ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 26
Author(s):  
Rui Zhou ◽  
Weicheng Gao ◽  
Wei Liu ◽  
Jianxun Xu
Keyword(s):  
Analytical Model ◽  
Cross Sections ◽  
Small Deviation ◽  
Tensile Modulus ◽  
Woven Fabric ◽  
Analytical Models ◽  
Uniaxial Tensile ◽  
Analytical Prediction ◽  
Woven Fabric Composites ◽  
Minimum Potential

With advantages in efficiency and convenience, analytical models using experimental inputs to predict the mechanical properties of plain-woven fabric (PWF) composites are reliable in guaranteeing the composites’ engineering applications. Considering the importance of the aspect above, a new analytical model for predicting the uniaxial tensile modulus of PWF is proposed in this article. The composite yarns are first simplified as the lenticular-shaped cross-sections undulate along arc-composed paths. Force analyses of the yarn segments are then carried out with the internal interactions simplified, and the analytical model is subsequently deduced from the principle of minimum potential energy and Castigliano’s second theorem. The PWF of T300/Cycom970 is chosen as the study object to which the proposed analytical model is applied. Microscopic observations and thermal ablation experiments are conducted on the specimens to obtain the necessary inputs. The uniaxial tensile modulus is calculated and tensile experiments on the laminates are performed to validate the analytical prediction. The small deviation between the experimental and analytical results indicates the feasibility of the proposed analytical model, which has good prospects in validating the effectiveness of the experimentally obtained modeling parameters and guaranteeing the accuracy of mesoscale modeling for the PWF.

scholarly journals Approximate Analytical Models of Shock-Wave Structure at Steady Mach Reflection

Fluids ◽  
2021 ◽  
Vol 6 (9) ◽  
pp. 305
Author(s):  
Mikhail V. Chernyshov ◽  
Karina E. Savelova ◽  
Anna S. Kapralova
Keyword(s):  
Experimental Data ◽  
Shock Wave ◽  
Comparative Analysis ◽  
Analytical Model ◽  
Mach Reflection ◽  
Supersonic Jet ◽  
Wave Structure ◽  
Analytical Models ◽  
Analytical Prediction ◽  
Shock Wave Structure

In this study, we obtain the comparative analysis of methods of quick approximate analytical prediction of Mach shock height in planar steady supersonic flows (for example, in supersonic jet flow and in narrowing channel between two wedges), that are developed since the 1980s and being actively modernized now. A new analytical model based on flow averaging downstream curved Mach shock is proposed, which seems more accurate than preceding models, comparing with numerical and experimental data.

A study on determination of tensile properties of metals at elevated temperatures from spherical indentation tests

2019 ◽  
Vol 54 (5-6) ◽  
pp. 331-347
Author(s):  
Tairui Zhang ◽  
Shang Wang ◽  
Weiqiang Wang
Keyword(s):  
Tensile Properties ◽  
Analytical Model ◽  
Elevated Temperatures ◽  
Regression Function ◽  
Maximum Error ◽  
Analytical Models ◽  
Uniaxial Tensile ◽  
Spherical Indentation ◽  
Material Parameters ◽  
Indentation Tests

In this study, spherical indentation tests were used to determine the uniaxial tensile properties of metals at elevated temperatures (200 °C, 400 °C, and 600 °C). Taking the difference between spherical indentation tests at room and elevated temperatures into consideration, the incremental and analytical models were used to determine material parameters ( σ0, Ep, and n) and thermal softening parameters ( Eeff and m) in the Johnson–Cook constitutive equation, respectively. A discussion on the stability of the analytical model proved that despite in relative complicated forms and with three intercoupling material parameters, the analytical model is still effective for tensile property calculation. From the investigation on the relationship between pm and pi, it was found that correlating coefficient ξ is actually a function of both indentation depth and material parameters, and thus, a regression function was proposed for a more accurate description of ξ. Effectiveness of the spherical indentation tests was verified through experiments on three steels, SA508, 15CrMoR, S30408, and one titanium alloy, TC21, which proved that the spherical indentation tests can provide both proof and tensile strength calculations with a maximum error around 15% at room temperature and within 20% at elevated temperatures, and thus satisfy the demands for engineering applications.

Stiffness Matrices of Woven Fabric Composites with Resin Cure

2010 ◽  
Vol 154-155 ◽  
pp. 526-530
Author(s):  
Mei Yang ◽  
Wei Xing Zhang ◽  
Qing Shen Zeng
Keyword(s):  
Theoretical Models ◽  
Unit Cell ◽  
Woven Fabric ◽  
Analytical Models ◽  
Degree Of Cure ◽  
Fiber Mats ◽  
Geometry Modeling ◽  
Woven Fabric Composites ◽  
Stiffness Matrices ◽  
Laminate Theory

Analytical models are presented for investigation of cure dependent stiffness of woven fiber composites. A linear-like correlation is adopted between the material properties and resin degree of cure. Fiber undulation model takes into account the fiber continuity and undulation and has been adopted for plain weave fiber mats geometry modeling. The analysis is performed on a unit cell, which is a representative of the entire fiber mat lamina. The classical laminate theory (CLT) is applied to determine stiffness constants in the infinitesimal region of the composites unit cell. The theoretical models can prediction the changes of stiffness matrices with the degree of cure. A case studies show that the elements of the stiffness matrices showed exponential increase with the resin degree of cure.

Elasto-Viscoplastic Analysis of Slanting-Weft Woven Fabric Composites Based on Homogenization Theory

2016 ◽  
Vol 725 ◽  
pp. 410-415
Author(s):  
Keita Goto ◽  
Takuya Tomioka ◽  
Masahiro Arai ◽  
Tetsuya Matsuda
Keyword(s):  
Tensile Load ◽  
Unit Cell ◽  
Woven Fabric ◽  
Homogenization Theory ◽  
Uniaxial Tensile ◽  
Analysis Model ◽  
Basic Cell ◽  
Woven Fabric Composites ◽  
Internal Structures ◽  
Fabric Composites

The elasto-viscoplastic behavior of slanting-weft woven laminates, the fiber bundles of which are not crossed at a right angle, is investigated both macroscopically and microscopically. For this, an analysis model for the [±θ] slanting-weft woven laminate with a cross angle ±θ and its diamond-shaped unit cell are considered. Then, a basic cell, which is quarter of the unit cell, is defined as an analysis domain by considering the point-symmetry of the internal structure. For the basic cell, the homogenization theory for nonlinear time-dependent composites with point-symmetric internal structures is applied. Using the present method, the elasto-viscoplastic analysis of the [±θ] slanting-weft woven laminates subjected to an in-plane uniaxial tensile load is performed. From the analysis results, the macroscopic elasto-viscoplastic behavior and the microscopic stress and strain distributions of the laminates are investigated.

Performance Optimization of Woven Fabric Composites for Printed Circuit Boards

1986 ◽  
Vol 72 ◽  
Author(s):  
Tsu-Wei Chou ◽  
Jenn-Ming Yang
Keyword(s):  
Performance Optimization ◽  
Printed Circuit Boards ◽  
Relative Effectiveness ◽  
Woven Fabric ◽  
Analytical Models ◽  
Circuit Boards ◽  
Materials Selection ◽  
Printed Circuit ◽  
Woven Fabric Composites ◽  
Fabric Composites

AbstractWoven fabric composites have been used extensively as substrate materials for multilayer printed circuit boards. This paper presents a brief overview of the recent accomplishments in the modeling and characterization of woven fabric composites. Three analytical models have been developed to predict the thermo-mechanical properties of fabric composites with various weaving geometries. A three-dimensional finite element analysis has also been adopted to determine the properties of plain-weave fabric composites.Parametric studies are performed for both hybrid and non-hybrid woven fabric composites to generate data for materials selection and design. These data are presented in the form of “structure-performance maps” where the unique characteristics and relative effectiveness of various woven fabric composites can be easily assessed. The potential of tailoring a low thermal expansion coefficient substrate material through suitable materials selection, geometrical design, and fiber hybridization is also discussed.

scholarly journals Novel Structure and Thermal Design and Analysis for CubeSats in Formation Flying

Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 150
Author(s):  
Yeon-Kyu Park ◽  
Geuk-Nam Kim ◽  
Sang-Young Park
Keyword(s):  
Analytical Model ◽  
Formation Flying ◽  
Thermal Environment ◽  
Thermal Analyses ◽  
Thermal Design ◽  
Analytical Models ◽  
Test Results ◽  
Solar Panels ◽  
Novel Structure ◽  
Micro Propulsion

The CANYVAL-C (CubeSat Astronomy by NASA and Yonsei using a virtual telescope alignment for coronagraph) is a space science demonstration mission that involves taking several images of the solar corona with two CubeSats—1U CubeSat (Timon) and 2U CubeSat (Pumbaa)—in formation flying. In this study, we developed and evaluated structural and thermal designs of the CubeSats Timon and Pumbaa through finite element analyses, considering the nonlinearity effects of the nylon wire of the deployable solar panels installed in Pumbaa. On-orbit thermal analyses were performed with an accurate analytical model for a visible camera on Timon and a micro propulsion system on Pumbaa, which has a narrow operating temperature range. Finally, the analytical models were correlated for enhancing the reliability of the numerical analysis. The test results indicated that the CubeSats are structurally safe with respect to the launch environment and can activate each component under the space thermal environment. The natural frequency of the nylon wire for the deployable solar panels was found to increase significantly as the wire was tightened strongly. The conditions of the thermal vacuum and cycling testing were implemented in the thermal analytical model, which reduced the differences between the analysis and testing.

The effects of geometric offsets on the dynamic responses of a Scott—Russell amplifying mechanism with flexible hinges

2009 ◽  
Vol 223 (10) ◽  
pp. 2413-2423 ◽  
Author(s):  
C-M Chen ◽  
R-F Fung
Keyword(s):  
Numerical Simulations ◽  
Analytical Model ◽  
Dynamic Responses ◽  
Analytical Models ◽  
Dynamic Equations ◽  
Magnification Factor ◽  
Flexure Hinges ◽  
Magnification Factors ◽  
Straight Line ◽  
Deviation Factor

The dynamic equations of a micro-positioning Scott—Russell (SR) mechanism associated with two flexible hinges and an offset are developed to calculate output responses. Both rigid and flexible hinges are considered to explore the results. The main features in the kinematics of the SR mechanism are its displacement amplification and straight-line motion, which are widely needed in practical industries. The manufacturing inaccuracy of the SR mechanism definitely causes geometric offsets of flexure hinges, and affects displacement amplification and straight-line output motion. Analytical models based on kinematics and Hamilton's principle are derived to explore the variation of linearity ratio, magnification factor, and deviation factor due to various offsets and link lengths. From numerical simulations for the SR mechanism with various offsets of flexible hinges in the conditions of different link lengths, it is found that offsets of flexure hinges obviously affect the amplifying factor and linearity ratio, and appear to dominate the changes of magnification factors. Moreover, an analytical model is also used to predict magnification factors due to various offsets. Finally, some conclusions concerning the effects of offset on the performance of the SR mechanism are drawn.

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