Foam mechanics: the linear elastic response of two-dimensional spatially periodic cellular materials

1987 ◽  
Vol 6 (1) ◽  
pp. 27-37 ◽  
Author(s):  
W.E. Warren ◽  
A.M. Kraynik
Keyword(s):  
Cellular Materials ◽  
Elastic Response ◽  
Two Dimensional ◽  
Linear Elastic ◽  
Spatially Periodic ◽  
Foam Mechanics

scholarly journals Activated Ductile CFRP NSMR Strengthening

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2821
Author(s):  
Jacob Wittrup Schmidt ◽  
Christian Overgaard Christensen ◽  
Per Goltermann ◽  
José Sena-Cruz
Keyword(s):  
Failure Modes ◽  
Elastic Response ◽  
Applied Theory ◽  
Strengthening Effect ◽  
The Novel ◽  
Near Surface ◽  
Linear Elastic ◽  
Near Surface Mounted ◽  
High Elongation ◽  
Strengthened Beam

Significant strengthening of concrete structures can be obtained when using adhesively-bonded carbon fiber-reinforced polymer (CFRP) systems. Challenges related to such strengthening methods are; however, the brittle concrete delamination failure, reduced warning, and the consequent inefficient use of the CFRP. A novel ductile near-surface mounted reinforcement (NSMR) CFRP strengthening system with a high CFRP utilization is introduced in this paper. It is hypothesized that the tailored ductile enclosure wedge (EW) end anchors, in combination with low E-modulus and high elongation adhesive, can provide significant strengthening and ductility control. Five concrete T-beams were strengthened using the novel system with a CFRP rod activation stress of approximately 980 MPa. The beam responses were compared to identical epoxy-bonded NSMR strengthened and un-strengthened beams. The linear elastic response was identical to the epoxy-bonded NSMR strengthened beam. In addition, the average deflection and yielding regimes were improved by 220% and 300% (average values), respectively, with an ultimate capacity comparable to the epoxy-bonded NSMR strengthened beam. Reproducible and predictable strengthening effect seems obtainable, where a good correlation between the results and applied theory was reached. The brittle failure modes were prevented, where concrete compression failure and frontal overload anchor failure were experienced when failure was initiated.

Implementation of p and h-p Versions of the Finite Element Method

1992 ◽  
Author(s):  
Ye-Chen Lai ◽  
Timothy C. S. Liang ◽  
Zhenxue Jia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Analysis ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Shape Functions ◽  
Linear Elastic ◽  
Finite Element Software ◽  
Analysis Process ◽  
Adaptive Analysis

Abstract Based on hierarchic shape functions and an effective convergence procedure, the p-version and h-p adaptive analysis capabilities were incorporated into a finite element software system, called COSMOS/M. The range of the polynomial orders can be varied from 1 to 10 for two dimensional linear elastic analysis. In the h-p adaptive analysis process, a refined mesh are first achieved via adaptive h-refinement. The p-refinement is then added on to the h-version designed mesh by uniformly increasing the degree of the polynomials. Some numerical results computed by COSMOS/M are presented to illustrate the performance of these p and h-p analysis capabilities.

An Experimental Study on Stretchy and Tough PDMS/Fabric Composites

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Ruofei Chang ◽  
Zhou Chen ◽  
Cunjiang Yu ◽  
Jizhou Song
Keyword(s):  
Fracture Toughness ◽  
Low Cost ◽  
Elastic Response ◽  
Deformation Localization ◽  
Practical Applications ◽  
Damage Propagation ◽  
Linear Elastic ◽  
Nylon Fabric ◽  
Fabric Composite ◽  
Fabric Composites

Polydimethylsiloxane (PDMS) has a good elasticity but with a pretty low fracture toughness, which limits its use in practical applications. This paper presents a simple and low-cost approach to manufacture a PDMS/fabric composite through incorporating the commercially available stretchy plain weft-knitted nylon fabric into the PDMS matrix. The fracture toughness of the composite is much higher than that of pure PDMS with an increase up to 700%. The toughening mechanism, which can be attributed to the deformation localization induced fiber stretch and damage propagation in the PDMS matrix, is fully investigated. During cyclic loadings, the composite may exhibit a linear elastic response or a significant hysteresis depending on the stretch level. These results provide physical insights into the deformation mechanism of a soft fabric-reinforced composite and may offer practical routes to realize robust crack-insensitive PDMS.

Scattering of a Rayleigh Wave by an Elastic Quarter Space

1985 ◽  
Vol 52 (3) ◽  
pp. 664-668 ◽  
Author(s):  
A. K. Gautesen
Keyword(s):  
Steady State ◽  
Surface Wave ◽  
Fourier Transforms ◽  
Two Dimensional ◽  
Rayleigh Surface Wave ◽  
State Problem ◽  
Free Surfaces ◽  
Linear Elastic ◽  
Quarter Space ◽  
Steady State Problem

We study the two-dimensional, steady-state problem of the scattering of waves in a homogeneous, isotropic, linear-elastic quarter space. We derive decoupled equations for the Fourier transforms of the normal and tangential displacements on the free surfaces. For incidence of a Rayleigh surface wave, we plot the amplitudes and phases of the surface waves reflected and transmitted by the corner. These curves were obtained numerically.

scholarly journals Membrane analogy for multi-material bars under torsion

2019 ◽  
Vol 475 (2225) ◽  
pp. 20190124 ◽  
Author(s):  
Laura Galuppi ◽  
Gianni Royer-Carfagni
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Cross Sections ◽  
Three Dimensional ◽  
Element Model ◽  
Elastic Problem ◽  
Two Dimensional ◽  
Torsion Problem ◽  
Linear Elastic ◽  
Physical Apparatus

Prandtl's membrane analogy for the torsion problem of prismatic homogeneous bars is extended to multi-material cross sections. The linear elastic problem is governed by the same equations describing the deformation of an inflated membrane, differently tensioned in regions that correspond to the domains hosting different materials in the bar cross section, in a way proportional to the inverse of the material shear modulus. Multi-connected cross sections correspond to materials with vanishing stiffness inside the holes, implying infinite tension in the corresponding portions of the membrane. To define the interface constrains that allow to apply such a state of prestress to the membrane, a physical apparatus is proposed, which can be numerically modelled with a two-dimensional mesh implementable in commercial finite-element model codes. This approach presents noteworthy advantages with respect to the three-dimensional modelling of the twisted bar.

Compressive Properties of Open Cell Aluminum Foams

2005 ◽  
Vol 486-487 ◽  
pp. 472-475 ◽  
Author(s):  
Bo Young Hur ◽  
Bu Keoun Park ◽  
Sang Youl Kim ◽  
Hoon Bae
Keyword(s):  
Aluminum Alloy ◽  
Strain Curve ◽  
Elastic Response ◽  
Aluminum Foams ◽  
Plateau Region ◽  
Lower Yield Stress ◽  
Open Cell ◽  
Linear Elastic ◽  
Open Cell Foam ◽  
Uniaxial Compressive Test

The uniaxial compressive test results of several aluminum foams are compared with aluminum alloy and ppi (pore per inch) of open cell foam. The compressive stress-strain curve of aluminum alloy foams exhibits universal three deformation regions: an initial linear elastic response, and then extended plateau region with a nearly constant flow stress, a final densification as collapsed cells are compacted together. The lower the foam densities are, the longer the plateau region is, but lower densities also imply lower yield stress.

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