Design of commercial hexagonal honeycombs of equal out-of-plane shear moduli

2019 ◽  
Vol 12 ◽  
pp. 309-318
Author(s):  
Ştefan Sorohan ◽  
Dan Mihai Constantinescu ◽  
Marin Sandu ◽  
Adriana Georgeta Sandu
Author(s):  
Mao Liu ◽  
W. D. Zhu

Abstract A major challenge in designing a perfect invisibility cloak for elastic waves is that density and elasticity tensors need to be independent functions of its radius with a linear transformation medium. The traditional cloak for out-of-plane shear waves in membranes exhibits material properties with inhomogeneous and anisotropic shear moduli and densities, which yields a poor or even negative cloaking efficiency. This paper presents design of a cylindrical cloak for shear waves based on a nonlinear transformation. This excellent broadband nonlinear cloak only requires variation of its shear modulus, while the density in the cloak region remains unchanged. The nonlinear ray trajectory equation for out-of-plane shear waves is derived and a parameter to adjust the efficiency of the cylindrical cloak is introduced. Qualities of the nonlinear invisibility cloak are discussed by comparison with those of a cloak with the linear transformation. Numerical examples show that the nonlinear cloak is more effective for shielding out-of-plane shear waves from outside the cloak than the linear cloak and illustrate that the nonlinear cloak for shear waves remains highly efficient in a broad frequency range. The proposed nonlinear transformation in conjunction with ray trajectory equations can also be used to design nonlinear cloaks for other elastic waves.


Buildings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 146 ◽  
Author(s):  
Jan Niederwestberg ◽  
Jianhui Zhou ◽  
Ying-Hei Chui

The lay-up of cross laminated timber (CLT) leads to significant differences in properties over its cross-section. Particularly the out-of-plane shear behavior of CLT is affected by the changes in shear moduli over the cross-section. Results from laboratory shear tests are used to evaluate the shear stiffness of 3- and 5-layer CLT panels in their major and minor strength direction. The results are compared to calculated shear stiffness values on evaluated single-layer properties as well as commonly used property ratios using the Timoshenko beam theory and the shear analogy method. Differences between the two calculation approaches are pointed out. The shear stiffness is highly sensitive to the ratio of the shear modulus parallel to the grain to the shear modulus perpendicular to the grain. The stiffness values determined from two test measurements are compared with the calculated results. The level of agreement is dependent on the number of layers in CLT and the property axis of the CLT panels.


Author(s):  
Jan Niederwestberg ◽  
Jianhui Zhou ◽  
Ying-Hei Chui

The lay-up of cross laminated timber (CLT) leads to significant differences in properties over its cross-section. Particularly the out-of-plane shear behavior of CLT is effected by the changes in shear moduli over the cross-section. Results from laboratory shear tests are used to evaluate the shear stiffness of 3- and 5-layer CLT panels in their major and minor strength direction. The results are compared to calculated shear stiffness values on evaluated single-layer properties as well as commonly used property ratios using the Timoshenko beam theory and the shear analogy method. Differences between the two calculation approaches are pointed out. The shear stiffness is highly sensitive to the ratio of the shear modulus parallel to the grain to the shear modulus perpendicular to the grain. The stiffness values determined from two test measurements are compared with the calculated results. The level of agreement is dependent on the number of layers in CLT and the property axis of the CLT panels.


2017 ◽  
Vol 172 ◽  
pp. 319-329 ◽  
Author(s):  
N. Tableau ◽  
Z. Aboura ◽  
K. Khellil ◽  
L. Marcin ◽  
F. Bouillon

Author(s):  
Ashish Kumar Srivastava ◽  
Vimal Kumar Pathak

In this article, the elastic and shear moduli of the graphene sheet-reinforced aluminum nanocomposite have been investigated by molecular dynamics simulations. Different models have been simulated to study the effect of multilayer graphene sheet, perforation of GS, and temperature on the elastic and shear moduli of resulting nanocomposite. The simulation results show that the elastic and shear moduli of graphene sheet-reinforced aluminum are sensitive to the temperature changes, multilayer, and perforated graphene sheets. The temperature and perforation of graphene sheets exert adverse effects on the elastic and shear moduli of graphene sheet-reinforced aluminum nanocomposites. However, the multilayer graphene sheet leads to favorable effects on the stiffness properties of the nanocomposite. It is also observed that there is only a marginal effect of the chirality of graphene sheet on the out-of-plane shear moduli of the nanocomposite.


2013 ◽  
Vol 564 ◽  
pp. 37-40 ◽  
Author(s):  
Balázs Hajgató ◽  
Songül Güryel ◽  
Yves Dauphin ◽  
Jean-Marie Blairon ◽  
Hans E. Miltner ◽  
...  

2021 ◽  
Vol 881 ◽  
pp. 149-156
Author(s):  
Mochamad Teguh ◽  
Novi Rahmayanti ◽  
Zakki Rizal

Building material innovations in various interlocking concrete block masonry from local materials to withstand lateral earthquake forces is an exciting issue in masonry wall research. The block hook has an advantage in the interlocking system's invention to withstand loads in the in-plane and out-of-plane orientations commonly required by the masonry walls against earthquake forces. Reviews of the investigation of in-plane and out-of-plane masonry walls have rarely been found in previous studies. In this paper, the results of a series of experimental tests with different interlocking models in resisting the simultaneous in-plane shear and out-of-plane bending actions on concrete blocks are presented. This paper presents a research investigation of various interlocking concrete blocks' mechanical properties with different hook thicknesses. Discussion of the trends mentioned above and their implications towards interlocking concrete block mechanical properties is provided.


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