Behzad D. Manshadi
École Polytechnique Fédérale de Lausanne
Biaxial tensile testUltimate tensile strengthEngineeringOrthotropic materialFinite element methodComposite laminatesTransverse planeComposite materialBridging (networking)Glass fiberCompression (physics)DiagramMaterials scienceGirderTension (physics)InstabilityShear forceRoofStress fieldConstant (mathematics)Fatigue damageStackingFiber Bragg gratingStructural engineeringFibre-reinforced plasticForensic engineeringSandwich-structured compositeBucklingShear (geology)
18Publications
7H-index
270Citations
Publications 18
Newest
#1Behzad D. Manshadi (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 7
#2Anastasios P. Vassilopoulos (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 28
Last. Thomas Keller (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 45
view all 3 authors...
Similarly to the post-buckling behavior of steel girder webs, the post-wrinkling behavior of glass fiber reinforced polymer (GFRP) cell-core sandwich webs can increase their ultimate shear strength. Post wrinkling is, however, different from post-buckling since wrinkling is a local buckling instability mode that can occur in any part of the web. Furthermore, all the previously presented theories or models have been limited to isotropic web plates, while the fiber architecture of orthotropic plat...
7 CitationsSource
#1Behzad D. Manshadi (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 7
#2E. Farmand-Ashtiani (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 1
Last. Anastasios P. Vassilopoulos (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 28
view all 4 authors...
Large scale bridging in mode-I delamination of layered composites is an important toughening mechanism. While its extent depends on constituent materials, it is also influenced by specimen geometry. Here, an analytical approach is adopted to express the through the thickness longitudinal strains in a double cantilever beam (DCB) specimen with the applied load and bridging tractions. The expression for the strains is confronted with strain data from embedded Bragg grating sensors to obtain bridgi...
26 CitationsSource
#1Behzad D. ManshadiH-Index: 7
Last. Thomas KellerH-Index: 45
view all 3 authors...
The aims of this research is to experimentally investigate the post-wrinkling behavior in GFRP cell-core sandwiches with orthotropic webs as well as the applicability of existing theories, e.g. the rotated stress field theory, to orthotropic FRP material systems. Through biaxial compression-tension experiments on web-core panels, the redistribution of the strain field during post-wrinkling was examined for two different fiber architectures, [90/0] and [±45] stacking sequences. The results prove ...
#1Behzad D. Manshadi (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 7
#2Anastasios P. Vassilopoulos (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 28
Last. John Botsis (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 37
view all 3 authors...
Bridging by intact fibers is an important toughening mechanism in composite materials. However, a direct experimental evaluation of its contribution is difficult to achieve and in the case of large scale bridging the thickness, h, may have an important influence on the energy release rate (ERR). In this work a semi-experimental method is adopted to quantify the effects of thickness to fracture of unidirectional glass fiber reinforced polymer (GFRP) double cantilever beam specimens in mode I frac...
35 CitationsSource
#1Behzad D. Manshadi (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 7
#2Anastasios P. Vassilopoulos (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 28
Last. Thomas Keller (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 45
view all 4 authors...
An analytical approach to determine the in-plane stress field and thereby the lateral contraction of composite rectangular plates subjected to partially uniform tension is presented. This approach is based on the Green function hypothesis and is able to accurately predict the in-plane stress field of orthotropic infinite and rectangular plate subjected to localized loading. The analytical predictions are compared to finite element and experimental results and found to be in good agreement. The m...
Source
#1Behzad D. Manshadi (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 7
#2Anastasios P. Vassilopoulos (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 28
Last. Thomas Keller (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 45
view all 4 authors...
A model for predicting the buckling and wrinkling behavior of glass-fiber-reinforced polymer (GFRP) plates and sandwich panels subjected to in-plane biaxial compression-tension loading is presented in this paper. In-plane biaxial compression-tension loading occurs in the webs of plate girders or cell-core sandwiches. The model is able to simulate two counteracting effects of increasing transverse tension load on buckling and wrinkling loads as observed in experiments. A stabilizing effect tends ...
4 CitationsSource
#1Behzad D. Manshadi (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 7
#2Anastasios P. Vassilopoulos (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 28
Last. Thomas Keller (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 45
view all 4 authors...
An analytical investigation of the buckling/wrinkling behavior of GFRP webs in cell-core sandwiches subjected to combined in-plane shear and bending stresses is conducted. Web-core panels are modeled as long orthotropic plates stabilized by a relatively thick layer of elastic foam. The boundary condition of the plate is defined according to the interaction between the webs and face sheets in the presence of the core material by applying a series of numerical analyses using the three-dimensional ...
6 CitationsSource
#1Behzad D. Manshadi (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 7
Last. Thomas KellerH-Index: 45
view all 4 authors...
An analytical investigation of the buckling/wrinkling behavior of GFRP webs in cell-core sandwiches subjected to combined in-plane shear and bending stresses is conducted. Webcore panels are modeled as long orthotropic plates stabilized by a relatively thick layer of elastic foam. Two approaches are adopted to predict the wrinkling behavior. The first is to predict the buckling/wrinkling of webs subjected to combined shear and bending loads using a mixed-mode interaction formula. In the second a...
Glass-fiber-reinforced polymer (GFRP) cell-core sandwiches are composed of outer GFRP face sheets, a foam core, and a grid of GFRP webs integrated into the core to reinforce the shear load capacity. One of the critical failure modes of cell-core sandwich structures is shear wrinkling, a local buckling failure in the sandwich webs because of shear loading. The shear wrinkling behavior of GFRP laminates with different laminate sequences, stabilized by a polyurethane foam core, was experimentally a...
7 CitationsSource
#1Behzad D. Manshadi (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 7
#2Anastasios P. Vassilopoulos (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 28
Last. Thomas Keller (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 45
view all 3 authors...
Thin webs of glass-fiber-reinforced polymer (GFRP) girders are sensitive to shear buckling, which can be considered an in-plane biaxial compression-tension buckling problem, according to the rotated stress field theory. An extensive experimental study was performed, which shows that an increasing transverse tension load significantly increases the buckling and ultimate loads caused by a decrease in the initial imperfections and additional stabilizing effects. The stacking sequence also greatly i...
11 CitationsSource