Experimental and numerical studies on compaction of carbon fiber composite joint with variable cross‐section using thermal expansion process

2018 ◽  
Vol 40 (S2) ◽  
pp. E1057-E1074 ◽  
Author(s):  
Weibo Zhang ◽  
Xuhao Liang ◽  
Min Li ◽  
Yizhuo Gu ◽  
Yanxia Li ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Carbon Fiber ◽  
Cross Section ◽  
Fiber Composite ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Expansion Process ◽  
Carbon Fiber Composite ◽  
Composite Joint ◽  
Numerical Studies

Experimental and numerical studies on buckling restrained braces with posttensioned carbon fiber composite cables

2020 ◽  
Vol 49 (15) ◽  
pp. 1640-1661
Author(s):  
Kurtulus Atasever ◽  
Shogo Inanaga ◽  
Toru Takeuchi ◽  
Yuki Terazawa ◽  
Oguz C. Celik
Keyword(s):  
Carbon Fiber ◽  
Fiber Composite ◽  
Carbon Fiber Composite ◽  
Numerical Studies ◽  
Buckling Restrained Braces

THE FRAGMENTATION OF THE TENSIONED ZONE OF THE STRENGTHENED REINFORCED CONCRETE BEAM WITH CARBON FIBER COMPOSITE

2010 ◽  
Vol 2 (4) ◽  
pp. 129-137 ◽  
Author(s):  
Gediminas Marčiukaitis ◽  
Mykolas Daugevičius ◽  
Juozas Valivonis
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Epoxy Resin ◽  
Fiber Composite ◽  
Composite Layer ◽  
Microscopic Analysis ◽  
Reinforced Concrete Beam ◽  
Carbon Fiber Composite ◽  
Composite Joint ◽  
Concrete Layer

The article analyzes the intensification influence of tensioned concrete on carbon fiber composite and concrete joint in a strengthened beam cracking manner. The paper calculates enlarged concrete compressive tensioned strength according to the impregnation of epoxy resin. The article figures out the level of epoxy resin penetration and deals with a microscopic analysis of concrete and carbon fiber composite joint. The presented modified calculation method of the cracking moment evaluates the characteristics of impregnated modified tensioned concrete. Four beams were tested. Two reinforced concrete beams were additionally strengthened with an external carbon fiber composite layer and loaded till failure. In addition, two reinforced beams without external reinforcement were tested. The accomplished experimental research of cracking strengthened beams showed that the calculated cracking moments with evaluated tensioned concrete layer intensification were more similar than the results without evaluation. After failure of strengthened beams, accomplished microscopic analysisof debonded carbon fiber composite layer. A microscopic analysis of concrete and carbon fiber composite joint was performed applying electronic microscope DG-3x. The thickness of the composite layer and modified tensioned concrete layer was measured using Micro Measure V 1.0 computer program. The accomplished microscopic analysis approved theoretical assumptions about epoxy resin penetration and distribution between aggregates. The strengthening of the reinforced concrete beam with carbon fiber composite improved mechanical characteristics of the tensioned concrete layer near concrete and carbon fiber composite joint. During strengthening, epoxy resin penetrates into concrete and fills micro cracks and pores. Thus, epoxy resin provides additional connections with aggregates. The calculated modified concrete tensioned strength and modulus of elasticity was respectively 3,0 and 1,9 times higher than that of ordinary concrete. Changes in concrete strength at the tensioned layer have influence on cracking manner because the ultimate deformation of modified concrete increases. Experimentally determined what evolution of vertical crack starts above the modified tensioned concrete layer at the joint with carbon fiber composite. Peeling the carbon fiber composite layer when the ultimate load level is reached also evolves above the modified tensioned concrete layer. The remained hydrated cement on the surface of the peeled external composite layer proves that shear stresses in the joint of concrete and carbon fiber composite reduced a weaker tensioned layer of concrete.

Prestressed Carbon Fiber Composite Overwrapped Gun Tube

2008 ◽  
Author(s):  
Andrew Littlefield ◽  
Edward Hyland ◽  
Jack Keating
Keyword(s):  
Carbon Fiber ◽  
Fiber Composite ◽  
Carbon Fiber Composite

Boundary element method in numerical study of three-dimensional Stokes flows in channels of arbitrary shape

2012 ◽  
Vol 9 (1) ◽  
pp. 94-97
Author(s):  
Yu.A. Itkulova
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Cross Section ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Periodic Flows ◽  
Element Method

In the present work creeping three-dimensional flows of a viscous liquid in a cylindrical tube and a channel of variable cross-section are studied. A qualitative triangulation of the surface of a cylindrical tube, a smoothed and experimental channel of a variable cross section is constructed. The problem is solved numerically using boundary element method in several modifications for a periodic and non-periodic flows. The obtained numerical results are compared with the analytical solution for the Poiseuille flow.

Longitudinal oscillation of a rod with a variable cross section

2019 ◽  
Vol 14 (2) ◽  
pp. 138-141
Author(s):  
I.M. Utyashev
Keyword(s):  
Cross Section ◽  
Natural Frequencies ◽  
Liouville Problem ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Independent Functions ◽  
The Cross ◽  
The Right

Variable cross-section rods are used in many parts and mechanisms. For example, conical rods are widely used in percussion mechanisms. The strength of such parts directly depends on the natural frequencies of longitudinal vibrations. The paper presents a method that allows numerically finding the natural frequencies of longitudinal vibrations of an elastic rod with a variable cross section. This method is based on representing the cross-sectional area as an exponential function of a polynomial of degree n. Based on this idea, it was possible to formulate the Sturm-Liouville problem with boundary conditions of the third kind. The linearly independent functions of the general solution have the form of a power series in the variables x and λ, as a result of which the order of the characteristic equation depends on the choice of the number of terms in the series. The presented approach differs from the works of other authors both in the formulation and in the solution method. In the work, a rod with a rigidly fixed left end is considered, fixing on the right end can be either free, or elastic or rigid. The first three natural frequencies for various cross-sectional profiles are given. From the analysis of the numerical results it follows that in a rigidly fixed rod with thinning in the middle part, the first natural frequency is noticeably higher than that of a conical rod. It is shown that with an increase in the rigidity of fixation at the right end, the natural frequencies increase for all cross section profiles. The results of the study can be used to solve inverse problems of restoring the cross-sectional profile from a finite set of natural frequencies.

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