The elastic constants and bond stresses for a three-dimensional composite reinforced by discontinuous fibers

1972 ◽  
Author(s):  
C. CHANG ◽  
H. CONWAY ◽  
T. WEAVER
Keyword(s):  
Elastic Constants ◽  
Three Dimensional

Structure, Elastic Constants and XRD Spectra of Extended Solids under High Pressure

MRS Advances ◽  
2018 ◽  
Vol 3 (8-9) ◽  
pp. 499-504 ◽  
Author(s):  
I.G. Batyrev ◽  
S.P. Coleman ◽  
J.A. Ciezak-Jenkins ◽  
E. Stavrou ◽  
J.M. Zaug
Keyword(s):  
Elastic Constants ◽  
Energetic Materials ◽  
Density Functional ◽  
Three Dimensional ◽  
Peak Position ◽  
X Ray Diffraction ◽  
Covalent Bonds ◽  
X Ray ◽  
Extended Solids ◽  
Xrd Patterns

ABSTRACTWe present results of evolutionary simulations based on density functional calculations of a potentially new type of energetic materials called extended solids: P-N and N-H. High-density structures with covalent bonds generated using variable and fixed concentration methods were analysed in terms of thermo-dynamical stability and agreement with experimental X-ray diffraction (XRD) spectra. X-ray diffraction spectra were calculated using a virtual diffraction algorithm that computes kinematic diffraction intensity in three-dimensional reciprocal space before being reduced to a two-theta line profile. Calculated XRD patterns were used to search for the structure of extended solids present at experimental pressures by optimizing data according to experimental XRD peak position, peak intensity and theoretically calculated enthalpy. Elastic constants has been calculated for thermodynamically stable structures of P-N system.

Numerical Analysis the Strain Distribution of GaN/AlN Self-Organized Pyramid Quantum Dot

2007 ◽  
Author(s):  
Yumin Liu ◽  
Zhongyuan Yu
Keyword(s):  
Quantum Dot ◽  
Green’S Function ◽  
Green's Function ◽  
Elastic Constants ◽  
Lattice Mismatch ◽  
Three Dimensional ◽  
Elastic Strain Energy ◽  
Self Organized ◽  
Contour Plots ◽  
Three Dimensional Finite Element

Based on the three-dimensional finite element approach, we investigate the strain field distribution of the GaN/AlN self-organized quantum dot. The truncated hexagonal pyramid quantum dot that has been found in experiment is adopted as the physical model in our simulation. The material elastic constants parameters used in this paper are of wurtzite structure, and there are five independent elastic constants. In dealing with the lattice mismatch, we employ a three-dimensional anisotropic pseudo-thermal expansion. We compare the calculated results with that calculated by Green’s function theory, in which many assumptions are made, and prove the correctness of our results. The strain distributions of the equal strain surface three-dimensional contour plots of the six strain components are given. Finally, the anisotropic characteristics of the GaN/AlN quantum dot material are discussed, the results demonstrate that the position of the elastic strain energy density minimum position is just located above the buried quantum dot and have no influence on the thickness of the capping layer. So the anisotropy has no obvious influence on the vertical alignment of post-growth of the next layer of quantum dots. Our model does not adopt the assumptions used in the Green’s function approach, so better reliability and precision of results are expected.

Visualization of Errors in Residual Stresses

1995 ◽  
Vol 39 ◽  
pp. 305-310
Author(s):  
R. W. Hendricks ◽  
H. D. Allison
Keyword(s):  
Residual Stresses ◽  
Stress Tensor ◽  
Elastic Constants ◽  
Three Dimensional ◽  
Triaxial Stress ◽  
Stress Calculation ◽  
Resultant Stress ◽  
True Values

Although it is widely known that small errors in d0 produce large errors in calculated components of the triaxial stress tensor, the magnitude and sign of errors in the elastic constants and do has not, thus tar, been visualized. In this study, the combined and isolated effects of errors on the resultant stress calculation is shown via three-dimensional, topographical, and onedimensional graphics. It has been found that stress is most sensitive to errors in d0, and least sensitive to S1. In most cases, errors lead to calculated stresses that differ from the true values by more than 20%, and in the worst cases change the magnitude by more than 200% and may even change the sign.

Equivalent Elastic Constants of Truss Core Sandwich Plates

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Hong-Xia Wang ◽  
Samuel W. Chung
Keyword(s):  
Elastic Constants ◽  
A Priori ◽  
Three Dimensional ◽  
Closed Form Solution ◽  
Elastic Stiffness ◽  
Form Solution ◽  
Laminated Plates ◽  
Element Analysis ◽  
Truss Core ◽  
Anisotropic Elastic

A plate structure of a triangular truss core sandwiched by two panels is treated as an equivalent homogeneous laminated plate by obtaining equivalent anisotropic elastic constants. The equivalent elastic constants are obtained by considering generalized Hook’s law of a three dimensional elastic body with no a priori assumption and the equilibrium of a segment deformed by bending moments. To verify the accuracy of the equivalent elastic constants, a linear static analysis of sandwiched aluminum plates subjected to lateral pressure is carried out. The results of the finite element analysis applied to the equivalent laminated plates are compared with those of a NASTRAN analysis of the original structural layouts. The results are also compared with a closed-form solution, which simplifies the sandwiched plate as a homogeneous orthotropic thick plate continuum (Lok and Cheng, 2000, “Elastic Stiffness Properties and Behavior of Truss-Core Sandwich Panel,” J. Struct. Eng., 126(5), pp. 552–559). As the maximum deflections of three analyses agreed closely, one has assurance that the method of the homogeneous plate with equivalent elastic constants is valid and useful.

scholarly journals Three Dimensional Parametric Analyses on Effect of Fibre Orientation for Stress Concentration Factor in Fibrous Composite Cantilever Plate with Central Circular Hole under Transverse Loading

2012 ◽  
Vol 13 (2) ◽  
Author(s):  
Nitin Jain ◽  
MOON Banerjee ◽  
Shubhashish Sanyal
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Elastic Constants ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Fibre Orientation ◽  
Fibrous Composite ◽  
Three Dimensional ◽  
Composite Plates ◽  
Transverse Loading

ABSTRACT: A number of analytical and numerical techniques are available for the two dimensional study of stress concentration around the hole(s) in isotropic and composite plates subjected to in-plane or transverse loading conditions. The information on the techniques for three dimensional analyses of stress concentration factor (SCF) around the hole in isotropic and composite plates subjected to transverse loading conditions is, however, limited. The present work emphasizes on the effect of fibre orientation (q) on the stress concentration factor in fibrous composite plates with central circular hole under transverse static loading condition. The work is carried out for cantilever fibrous composite plates. The effects of thickness -to- width (T/A) and diameter-to-width (D/A) ratios upon SCF at different fibre orientation are studied. Plates of four different composite materials were considered for hole analysis in order to determine the sensitivity of SCF with elastic constants. Deflections in transverse direction were calculated and analysed. All results are presented in graphical form and discussed. The finite element formulation and its analysis were carried out using ANSYS package.ABSTRAK: Terdapat pelbagai teknik analitikal dan numerical untuk kajian tumpuan tegasan dua dimensi di sekeliling lubang-lubang dalam komposit isotropik dan plat pada satah atau keadaan bebanan melintang. Bagaimanapun, maklumat mengenai kaedah analisis tiga dimensi untuk faktor ketumpatan tegasan (SCF) sekitar lubang dalam komposit isotropik dan plat pada keadaan bebanan melintang adalah terhad. Kertas ini menekankan kesan orientasi gentian (q) pada faktor tumpuan tegasan dalam komposit plat bergentian dengan lubang berpusat di bawah keadaan bebanan melintang. Kajian ini dilkukan untuk cantilever plat komposit bergentian. Kesan ketebalan terhadap kelebaran plat (T/A) dan diameter terhadap kelebaran komposit (D/A) dengan SCF pada orientasi gentian berbeza telah dikaji. Plat komposit bagi empat bahan komposit berbeza telah diambilkira bagi kesemua analisis untuk mendapatkan kesensitifan SCF dengan konstan elastic. Defleksi pada arah melintang telah dikira dan dianalisa. Kesemua keputusan telah disembahkan secara grafik dan dibincang. Fomulasi unsur finit dan analisis telah dilaksanakan menggunakan pakej ANSYS.KEYWORDS:          finite element method; stress concentration factor; composites; transverse loading; deflection; elastic constants

Sign in / Sign up

Export Citation Format

Share Document