A Hybrid Experimental-Numerical Test Specimen for Laminated Composite Materials

1991 ◽  
Vol 113 (3) ◽  
pp. 193-196
Author(s):  
W. K. Rule ◽  
G. E. Weeks
Keyword(s):  
Numerical Test ◽  
Cost Savings ◽  
Laminated Composite ◽  
Uniaxial Stress ◽  
Testing Procedure ◽  
Biaxial Stress ◽  
Element Analysis ◽  
Laminated Composite Materials ◽  
Stress States ◽  
A New Technique

A new technique is described for determining all four elastic constants of a lamina from a single laminated specimen of arbitrary, symmetric lay-up. This specimen is subjected to three different loading conditions, and the experimental data is reduced by means of a finite element analysis. The testing procedure for the specimen is relatively easy, which can result in considerable time and cost savings over traditional methods. The new specimen generates biaxial stress states. Thus, the material properties determined from such a configuration may be more appropriate for later use in structural analysis than those determined from traditional specimens with uniform uniaxial stress states.

Analysis of In-Plane Compression and Bending of Honeycombs With Laminated Cell Walls

2015 ◽  
Author(s):  
Ruoshui Wang ◽  
Jyhwen Wang
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Material Selection ◽  
Computational Cost ◽  
Cost Savings ◽  
Laminated Composite ◽  
Element Analysis ◽  
Honeycomb Structures ◽  
Plane Compression ◽  
Elastic Responses

Using laminated composite cell walls in honeycomb structures can bring potential advantages such as increased specific stiffness, greater options for material selection, and very importantly, improved manufacturing efficiency. In this paper, the in-plane elastic responses of honeycomb structures with laminated composite cell wall are investigated. An analytical model was developed to obtain the effective elastic properties of the honeycombs based on the laminate properties of the cell wall. The derived homogenization properties were then used to predict the in-plane compression and bending behaviors of the structures. The predicted results were compared with those from finite element analysis of the full detailed honeycomb models. The results of the homogenized solid model, with significant computational cost savings, were in good agreement with those of honeycomb models with full geometric details. It was also demonstrated that the proposed model can be effectively and efficiently used for composite cell wall design and material selection.

Measurement of Biaxial Stress States in Silicon Using Micro-Raman Spectroscopy

2006 ◽  
Vol 73 (5) ◽  
pp. 745-751 ◽  
Author(s):  
Peter A. Gustafson ◽  
Stephen J. Harris ◽  
Ann E. O’Neill ◽  
Anthony M. Waas
Keyword(s):  
Raman Spectroscopy ◽  
Uniaxial Stress ◽  
Laboratory Frame ◽  
Silicon Wafers ◽  
Biaxial Stress ◽  
Micro Raman Spectroscopy ◽  
Multiaxial Stress State ◽  
Stress States ◽  
Stress Ratios

Micro-Raman spectroscopy is used to determine the multiaxial stress state in silicon wafers using a strategy proposed by Narayanan, et al. (J. Appl. Phys. 82, 2595–2602 (1997)) Previously, this strategy was validated when silicon was subjected to uniaxial stress in the laboratory frame (Harris, et al. J. Appl. Phys. 96, 7195–7201 (2004)). In the present work, silicon wafers have been analyzed that were subjected to biaxial stress states in the laboratory frame. The predicted curves for the initially degenerate F2g peaks were found to fall within the variability of the measured curves. Stress ratios were found to be predictable. Stress magnitudes were also found to be predictable, but are subject to uncertainty greater than 25%. To perform these tests, an apparatus has been developed which can provide controlled ratios of biaxial stress in a simple and compact test geometry. This fixture was used under a microscope, enabling in situ measurement of biaxial stress states.

Verification of a Manual Mesh Moving Finite Element Analysis Procedure for Modeling Ablation in Laminated Composite Materials

2017 ◽  
Author(s):  
Yeqing Wang ◽  
Olesya I. Zhupanska ◽  
Crystal L. Pasiliao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Materials ◽  
Laminated Composite ◽  
General Purpose ◽  
Composite Panel ◽  
Arbitrary Lagrangian Eulerian ◽  
Element Analysis ◽  
Laminated Composite Materials ◽  
Cfrp Composite

One of the prevalent approaches to model ablation problems is to use the UMESHMOTION subroutine and the Arbitrary Lagrangian-Eulerian (ALE) adaptive remesh algorithm in ABAQUS (i.e., a commercial, general purpose Finite Element Analysis (FEA) software). However, the approach is not applicable for ablation problems when the material removal proceeds from one material domain to another, such as for ablations of laminated composite materials when the surface recedes from one laminate layer to another layer with different material orientations. In this paper, a novel procedure, based on manual mesh moving FEA with ABAQUS, is proposed to solve the ablation problems for laminated composite materials. The proposed procedure is verified by comparing the predictions of temperature and ablation histories of a two-dimensional isotropic panel (i.e., with single material domain) with those obtained using the traditional UMESHMOTION+ALE method. In addition, a case study is presented to demonstrate the successful application of the proposed procedure for the prediction of the thermal and ablation response of a laminated carbon fiber reinforced epoxy matrix (CFRP) composite panel subjected to a high-intensity and short-duration radiative heat flux.

Об особенностях использования явления акустоупругости при контроле напряженного состояния анизотропного материала технических объектов при отрицательных температурах

2021 ◽  
pp. 23-32
Author(s):  
А.А. Хлыбов ◽  
А.Л. Углов ◽  
Д.А. Рябов
Keyword(s):  
Stress State ◽  
Uniaxial Stress ◽  
Modern Method ◽  
Biaxial Stress ◽  
Transverse Waves ◽  
Acoustic Anisotropy ◽  
Biaxial Stress State ◽  
Calculation Algorithms ◽  
Arctic Conditions ◽  
Stress States

The paper considers the features of using the modern method of acoustoelasticity for monitoring the uniaxial and biaxial stress state of acoustically anisotropic structural materials as part of technical objects operated in Arctic conditions. The features of using the method of acoustoelasticity for materials with different values of acoustoelastic coefficients, acoustic anisotropy and temperature dependence coefficients of acoustic parameters that appear in the calculation algorithms are analyzed. It has been established that the existing approaches to taking into account temperature effects in acoustoelastic calculations in a number of important cases lead to noticeable errors in determining mechanical stresses in the material of critical technical objects. In this case, taking into account the temperature corrections in a number of cases is necessary for both biaxial (planar) and uniaxial stress states. The presence of anisotropy of thermoacoustic coefficients of transverse waves for materials with anisotropy is shown experimentally. Refined calculation formulas are proposed for determining the uniaxial and biaxial stress state of an anisotropic material, taking into account the anisotropy of the thermoacoustic coefficients of transverse waves.

Experimental Studies of Biaxially Stressed Mild Steel in the Plastic Range

1948 ◽  
Vol 15 (3) ◽  
pp. 193-200
Author(s):  
S. J. Fraenkel
Keyword(s):  
Strain Path ◽  
Room Temperature ◽  
Stress Ratio ◽  
Experimental Studies ◽  
Uniaxial Stress ◽  
Biaxial Stress ◽  
Plastic Range ◽  
Static Tests ◽  
Stress States ◽  
Tubular Specimens

Abstract This paper describes static tests of tubular specimens of medium steel under biaxial stresses and at room temperature. The purposes of the tests were: (1) to obtain an experimental check on the so-called “third rule of plastic flow;” (2) to study the absorption of energy as a function of the biaxial stress ratio; and (3) to determine the effect of the path of loading as symbolized by the strain path. Within the range of conditions investigated, the path of loading was found to be immaterial. A relation between strain energies absorbed under biaxial and uniaxial stress states up to a common maximum strain is tentatively formulated.

Stress and conditions of continuity of laminated composite materials

1974 ◽  
Vol 10 (4) ◽  
pp. 394-401 ◽  
Author(s):  
V. A. Kolgadin ◽  
G. P. Bogatyr' ◽  
V. I. �tokova
Keyword(s):  
Composite Materials ◽  
Laminated Composite ◽  
Laminated Composite Materials
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