Browsing by Author "Sachin, S."

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Experimental investigation of mode I interlaminar fracture toughness in T300/914 composite
(Elsevier Ltd, 2020) Sachin, S.; Nayaka, S.H.; Santhosh, B.; Krishna, P.
An aerospace structural material T300/914 has been studied to understand the Mode I interlaminar fracture toughness. For experimental analysis a Double Cantilever Beam (DCB) test is conducted on the laminate to estimate the Mode I interlaminar fracture toughness of the sample. A 48-layer laminate was prepared by hand layup process and an insert included at the mid plane to produce the artificial initial crack required for the test. All the tests are conducted in accordance to the ASTM standards. Pulse-Echo test results and C-Scan images of the laminate were analyzed to find the defects in the laminate. The data from DCB test were analyzed by Modified Beam theory, Compliance calibration method and modified compliance calibration methods to find the interlaminar fracture toughness. A crack length correction method is implemented for data reduction. Numerical analysis of the data derives results in accordance with the experimental analysis. Â© 2019 Elsevier Ltd. All rights reserved.
Experimental study of Mode i and Mode II interlaminar fracture toughness on aerospace structural composite T300/914
(2019) Sachin, S.; Nayaka, H.S.; Santhosh, B.; Krishna, P.
Carbon epoxy composite T300/914 which has wide applications in aerospace industries, as a structural material, has been analyzed, to determine the interlaminar fracture toughness. Laminates with a thickness of 4.6 mm, consisting of 48 layers of T300/914, are considered for estimating the inter-laminar fracture toughness. These specimens have been fabricated by hand layup method followed by controlled curing in an autoclave. Tests have been conducted in accordance with ASTM standards, for Mode I by Double Cantilever Beam (DCB) test and End Notch Flexure (ENF) test for Mode II. Pulse-Echo test results and C-Scan images of the specimens were also analyzed to locate the exact position of delamination. During the preliminary tests, it was found that the interlaminar fracture toughness varied, because of bonding of release film with the sides of the laminate. By Modified Beam Theory, Mode I and Mode II fracture toughness values of the prepared specimens were found to be 0.090 kJ/m2and 0.542 kJ/m2, respectively. It was also noted that the fracture toughness of the specimens from the same laminate varied with the degree of compaction. � 2018 Author(s).
Experimental study of Mode i and Mode II interlaminar fracture toughness on aerospace structural composite T300/914
(American Institute of Physics Inc. subs@aip.org, 2019) Sachin, S.; Shivananda Nayaka, H.S.; Santhosh, B.; Krishna, P.
Carbon epoxy composite T300/914 which has wide applications in aerospace industries, as a structural material, has been analyzed, to determine the interlaminar fracture toughness. Laminates with a thickness of 4.6 mm, consisting of 48 layers of T300/914, are considered for estimating the inter-laminar fracture toughness. These specimens have been fabricated by hand layup method followed by controlled curing in an autoclave. Tests have been conducted in accordance with ASTM standards, for Mode I by Double Cantilever Beam (DCB) test and End Notch Flexure (ENF) test for Mode II. Pulse-Echo test results and C-Scan images of the specimens were also analyzed to locate the exact position of delamination. During the preliminary tests, it was found that the interlaminar fracture toughness varied, because of bonding of release film with the sides of the laminate. By Modified Beam Theory, Mode I and Mode II fracture toughness values of the prepared specimens were found to be 0.090 kJ/m2and 0.542 kJ/m2, respectively. It was also noted that the fracture toughness of the specimens from the same laminate varied with the degree of compaction. Â© 2018 Author(s).
Investigation of microstructure and mechanical properties of Cu-Ni alloy processed by equal channel angular pressing
(SAGE Publications Ltd, 2023) Sachin, S.; Nayaka H, S.
The Copper-Nickel alloy, C70600, was subjected to severe plastic deformation by the equal channel angular pressing (ECAP) technique. The material was pressed at room temperature along route BC for eight passes. Microstructural analysis and mechanical characterization of the material were done for each of the ECAP pass samples. The initial homogenized material having equiaxial grains of average grain size 75 µm was reduced to 20 µm after eight ECAP passes. Electron backscatter diffraction data presented an increase in low angle grain boundaries with an increase in the number of ECAP passes. Initially, the ultimate tensile strength and the hardness increased by 56% and 94% respectively. After the fifth ECAP pass, a drastic reduction in ultimate tensile strength and ductility was witnessed. Hardness value remained constant after the fifth ECAP pass. Fractography analysis indicate the ductile mode of fracture with reduced dimple size at higher ECAP passes. © The Author(s) 2022.
Microstructural Study and Mechanical Characterization of ECAP Processed C70600 Alloy
(Springer, 2022) Sachin, S.; Shivananda Nayaka, H.S.
Copper–Nickel alloy C70600 was processed by equal channel angular pressing (ECAP), at room temperature, up to 8 passes, to study the mechanical properties and metallurgical behavior Microstructural studies showed grain refinement up to fourth ECAP pass. Microhardness value increased by 45% after 4 ECAP passes. With further increase in ECAP passes, samples attained a saturated state. Similar trend was observed in Ultimate tensile strength with an increase of 54% as compared to homogenized sample and reached a maximum value of 562 MPa. Increase in mechanical property was attributed to strengthening by grain refinement and dislocation strengthening. XRD analysis showed the absence of precipitate in the deformed specimens. © 2022, The Institution of Engineers (India).