Study on residual stresses in epoxy composites with disperse fillers caused by the parameters of external surface layers

A series of experiments on measuring of difference between the main mechanical stresses (DPMS) was carried out using a mechanical stress scanner based on the magnetoanisotropic method. The magnitude of the DPMS is fixed when a magnetic field is induced on a carbon steel plate under uniaxial tension. A direct proportional relationship is shown between the magnitude of the DPMS signal recorded by the scanner and the magnitude of tensile stresses in the plate in the region of elastic deformation of steel. Measurement of the DPMS signal in the central part of similar plates previously subjected to elastic-plastic bending showed that positive values of the signal are fixed in the surface layers of the metal on the inside of the plate, which corresponds to tensile residual stresses, while the negative ones concentrate at the external surface, which corresponds to compressive stresses. A transverse incision on a curved plate from the inside leads to a decrease in the value of the signal of the DPMS, which indicates a decrease in the level of residual stresses in the metal. The values of the DPMS signal in the central part of the curved plate, recalculated using the established calibration dependence on the value of the residual stresses, were compared with the values of the stresses established by calculation, based on the Henki’s theorem on the unloading of an elastic-plastic body. A satisfactory convergence was obtained between the experimental and calculated data.

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Regularities of Impact Failure of Epoxy Composites with Al2O3 Microfiller and their Analysis on the Basis of External Surface Layer Concept

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.712.149 ◽

2016 ◽

Vol 712 ◽

pp. 149-154

Author(s):

Andriy Buketov ◽

Petro Stukhlyak ◽

Pavlo Maruschak ◽

Sergey V. Panin ◽

Abdellah Menou

Keyword(s):

Mechanical Properties ◽

Surface Layer ◽

Composite Materials ◽

Impact Toughness ◽

External Surface ◽

Epoxy Composite ◽

Epoxy Composites ◽

Surface Layers ◽

Disperse Filler ◽

Layer Concept

Impact toughness of epoxy composite materials reinforced with Al2O3 microparticles of various concentrations were investigated. It is shown that the external (outer) surface layers that form around disperse filler particles is one of the factor responsible their mechanical properties.

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Physical and Chemical Aspects of Formation of Epoxy Composite Material with Microfilling Agent

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.712.143 ◽

2016 ◽

Vol 712 ◽

pp. 143-148 ◽

Cited By ~ 1

Author(s):

Andriy Buketov ◽

Petro Stukhlyak ◽

Pavlo Maruschak ◽

Sergey V. Panin ◽

Abdellah Menou

Keyword(s):

Composite Material ◽

Structure Formation ◽

External Surface ◽

Epoxy Composite ◽

Epoxy Composites ◽

Surface Layers ◽

Disperse Filler ◽

Filler Particles ◽

Physical And Chemical

Formation of epoxy composite material with microfilling agent Al2O3 was investigated. Physical and chemical aspects of formation of external surface layers around disperse filler particles during structure formation of epoxy composites was proposed.

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Formation of residual stresses in the surface layers of targets from titanium alloys under irradiation with high-current pulsed electron beams

Physics and Chemistry of Materials Treatment ◽

10.30791/0015-3214-2018-2-69-73 ◽

2018 ◽

pp. 69-73

Author(s):

V.A. Shulov ◽

◽

I.G. Steshenko ◽

D.A. Teryaev ◽

Yu.A. Perlovich ◽

...

Keyword(s):

Residual Stresses ◽

Titanium Alloys ◽

Electron Beams ◽

High Current ◽

Surface Layers

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Fatigue Life Improvement of Welded Elements and Structures by Ultrasonic Impact Treatment

Volume 3: Materials Technology; Jan Vugts Symposium on Design Methodology of Offshore Structures; Jo Pinkster Symposium on Second Order Wave Drift Forces on Floating Structures; Johan Wichers Symposium on Mooring of Floating Structures in Waves ◽

10.1115/omae2011-50310 ◽

2011 ◽

Author(s):

Yuriy Kudryavtsev ◽

Jacob Kleiman

Keyword(s):

Mechanical Properties ◽

Fatigue Life ◽

Fatigue Strength ◽

Residual Stresses ◽

Fatigue Testing ◽

Highway Bridges ◽

Surface Layers ◽

Ultrasonic Impact Treatment ◽

Stress Relieving ◽

Life Improvement

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

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