DESIGN AND ASSESSMENT OF STEEL AND STEEL-CONCRETE COMPOSITE STRUCTURES: EFFICACY OF EN1998 DESIGN PROCEDURE

2014 ◽  
Author(s):  
A. Braconi ◽  
S. Caprili ◽  
H. Degée ◽  
M. Guendel ◽  
M. Hjaij ◽  
...  
Keyword(s):  
Composite Structures ◽  
Design Procedure

METAMODELING METHODOLOGY FOR POSTBUCKLING SIMULATION OF DAMAGED COMPOSITE STIFFENED STRUCTURES WITH PHYSICAL VALIDATION

2010 ◽  
Vol 10 (04) ◽  
pp. 705-716 ◽  
Author(s):  
KASPARS KALNINS ◽  
ROLANDS RIKARDS ◽  
JANIS AUZINS ◽  
CHIARA BISAGNI ◽  
HAIM ABRAMOVICH ◽  
...  
Keyword(s):  
Composite Structures ◽  
Design Procedure ◽  
Computer Experiments ◽  
Design Guidelines ◽  
Design Tool ◽  
Piecewise Linear Approximation ◽  
Stiffened Panel ◽  
Response Curves ◽  
Damage Scenarios ◽  
Stiffened Structures

A metamodeling methodology has been proposed for postbuckling simulation of stiffened composite structures with integrated degradation scenarios. The presence of artificial damage between the outer skin and stiffeners has been simulated as softening of the material properties in predetermined regions of the structure. The proposed methodology for the fast design procedure of axially or torsionally loaded stiffened composite structures is based on response surface methodology (RSM) and design and analysis of computer experiments (DACE). Numerical analyses have been parametrically sampled by means of the ANSYS/LS-DYNA probabilistic design toolbox extracting the load-shortening response curves in the preselected domain of interest. These response curves have been simplified using piecewise linear approximation identifying the buckling and postbuckling stiffness ratios along with the values of the skin and the stiffener buckling loads. Three stiffened panel designs and a closed box structure with preselected damage scenarios have been elaborated and validated with the tests performed within the COCOMAT project. The resulting design procedure provides a time-effective design tool for preliminary study and for elaboration of the optimum design guidelines for composite stiffened structures with material degradation restraints.

Optimization design, manufacturing and mechanical performance of box girder made by carbon fiber-reinforced epoxy composites

2018 ◽  
Vol 25 (2) ◽  
pp. 297-307 ◽  
Author(s):  
Bin Yang ◽  
Lili Tong ◽  
Cheav Por Chea
Keyword(s):  
Composite Structures ◽  
Optimization Design ◽  
High Efficiency ◽  
Mechanical Performance ◽  
Parametric Design ◽  
Design Procedure ◽  
Optimization Procedure ◽  
Experimental Tests ◽  
Bending Test ◽  
Box Girder

AbstractOptimization design and manufacturing play an important role in obtaining successful composite structures with high efficiency and safe use of materials. In this paper, we first present the optimization design procedure for a composite box girder by ANSYS parametric design language (APDL) in the ANSYS software. The input parameters used in the simulation work were determined via fundamental experimental tests of composite specimens. Then we manufactured the designed composite box girder by mold-pressing prepreg technology according to the optimization results. The finial composite girder structure composed of arch top, web and bottom composite plate was obtained. The optimization procedure indicated that the use of stiffening plates in a girder could decrease the weight and increase the failure load. The location and ply mode of the stiffening plates in girder were suggested. The three-point-bending test was performed on the girder, and the test indicated that load-carrying capacity in unit mass of the optimized girder was as high as 107.8 N/g. Simulation and experimental results match well, and the maximum and minimum stresses in each layer were within the strength limitation of carbon material after optimized in the procedure.

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

A Numerical and Experimental Approach for Modeling Porosity Due to Entrapped Air and Volatiles Off-gassing During Manufacturing of Composite Structures

2019 ◽  
Author(s):  
Curtis Hickmott ◽  
Alireza Forghani ◽  
Victoria Hutten ◽  
Evan Lorbiecki ◽  
Frank Palmieri ◽  
...  
Keyword(s):  
Composite Structures ◽  
Experimental Approach ◽  
Entrapped Air

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Application of Computational Mechanics to Tire Design—Yesterday, Today, and Tomorrow

2011 ◽  
Vol 39 (4) ◽  
pp. 223-244 ◽  
Author(s):  
Y. Nakajima
Keyword(s):  
Finite Element ◽  
New Technologies ◽  
Computational Mechanics ◽  
Design Procedure ◽  
Side Wall ◽  
Rolling Resistance ◽  
Optimization Techniques ◽  
Stress Strain ◽  
Element Analysis ◽  
Crown Shape

Abstract The tire technology related with the computational mechanics is reviewed from the standpoint of yesterday, today, and tomorrow. Yesterday: A finite element method was developed in the 1950s as a tool of computational mechanics. In the tire manufacturers, finite element analysis (FEA) was started applying to a tire analysis in the beginning of 1970s and this was much earlier than the vehicle industry, electric industry, and others. The main reason was that construction and configurations of a tire were so complicated that analytical approach could not solve many problems related with tire mechanics. Since commercial software was not so popular in 1970s, in-house axisymmetric codes were developed for three kinds of application such as stress/strain, heat conduction, and modal analysis. Since FEA could make the stress/strain visible in a tire, the application area was mainly tire durability. Today: combining FEA with optimization techniques, the tire design procedure is drastically changed in side wall shape, tire crown shape, pitch variation, tire pattern, etc. So the computational mechanics becomes an indispensable tool for tire industry. Furthermore, an insight to improve tire performance is obtained from the optimized solution and the new technologies were created from the insight. Then, FEA is applied to various areas such as hydroplaning and snow traction based on the formulation of fluid–tire interaction. Since the computational mechanics enables us to see what we could not see, new tire patterns were developed by seeing the streamline in tire contact area and shear stress in snow in traction.Tomorrow: The computational mechanics will be applied in multidisciplinary areas and nano-scale areas to create new technologies. The environmental subjects will be more important such as rolling resistance, noise and wear.

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