Dr. K P Narayananhttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/46742024-02-07T17:54:24Z2024-02-07T17:54:24ZA Comparative Study Of Tensile And Microstructural Characteristics Of Friction Welded Joints And Conventionally Welded Joints Of Aluminium Alloy 6061Narayanan, K PBaiju, SasidharanAneesh, K Nhttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/46772014-08-21T20:30:32Z2013-12-01T00:00:00ZA Comparative Study Of Tensile And Microstructural Characteristics Of Friction Welded Joints And Conventionally Welded Joints Of Aluminium Alloy 6061
Narayanan, K P; Baiju, Sasidharan; Aneesh, K N
Welding of high strength and low weight materials like Aluminium Alloys without any defects by conventional
welding techniques is a major challenge in industries. Hence research on solid state welding techniques like Friction
stir welding and Friction welding techniques have got much importance in joining of Aluminium alloys. However
most of the industries are not changing conventional techniques as skilled workers are available on that area. Most
common conventional welding techniques used for joining of Aluminium alloys are Gas welding and Arc welding.
Friction welding is a solid-state welding process that generates heat through mechanical friction between a moving
and a stationary component with the addition of a lateral force called “upset” to plast ically displace and fuse the
materials. In this work, experimental study on tensile and micro structural characteristics of welded joints formed
from conventional welding techniques and Rotary friction welding(suitable for weld specimens with circular cross
section) has been carried out and the same were compared. The process parameters for arc welding used was 50-70
Amp reverse polarity DC and electrodes of 2.3mm diameter. In Gas welding, the parameters were oxy acetylene
neural flame at 3200°C and 3mm electrodes . In the case of friction welding an axial pressure loading of 3Mpa with
5 MPa as upsetting pressure and 500 rpm were used to obtain good welded joints. Tensile characteristic studies of
Arc welded joints and Gas welded joints showed 48% and 60 % variations respectively from the maximum load
bearing characteristics of parent metal. In the case of friction welded joint, the variation was found to 46%. Micro
structural evaluation of conventionally welded joints exhibited clear distinct zones of various weld regions. In the
case of friction welded joint micro structural photographs showed comparable features both in parent metal and
welded region. Thus the tensile characteristic study and microstructure evaluations proved that friction welded joints
are good in both aspects compared to conventionally welded joints.
International Journal of Innovative Research in Science, Engineering and Technology,Volume 2, Special Issue 1, December 2013
2013-12-01T00:00:00ZPerformance Assessment of Sandwich Structures with Debonds and DentsNarayanan, K PPradeep, K RAnju, Mohananhttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/46762014-08-21T20:30:31Z2013-05-01T00:00:00ZPerformance Assessment of Sandwich Structures with Debonds and Dents
Narayanan, K P; Pradeep, K R; Anju, Mohanan
A sandwich construction is a special form of the laminated composite consisting of light weight core, sandwiched between two stiff thin
face sheets. Due to high stiffness to weight ratio, sandwich construction is widely adopted in aerospace industries. As a process dependent bonded
structure, the most severe defects associated with sandwich construction are debond (skin core bond failure) and dent (locally deformed skin
associated with core crushing). Reasons for debond may be attributed to initial manufacturing flaws or in service loads and dent can be caused by
tool drops or impacts by foreign objects. This paper presents an evaluation on the performance of honeycomb sandwich cantilever beam with the
presence of debond or dent, using layered finite element models. Dent is idealized by accounting core crushing in the core thickness along with the
eccentricity of the skin. Debond is idealized using multilaminate modeling at debond location with contact element between the laminates.
Vibration and buckling behavior of metallic honeycomb sandwich beam with and without damage are carried out. Buckling load factor, natural
frequency, mode shape and modal strain energy are evaluated using finite element package ANSYS 13.0. Study shows that debond affect the
performance of the structure more severely than dent. Reduction in the fundamental frequencies due to the presence of dent or debond is not
significant for the case considered. But the debond reduces the buckling load factor significantly. Dent of size 8-20% of core thickness shows 13%
reduction in buckling load capacity of the sandwich column. But debond of the same size reduced the buckling load capacity by about 90%. This
underscores the importance of detecting these damages in the initiation level itself to avoid catastrophic failures. Influence of the damages on
fundamental frequencies, mode shape and modal strain energy are examined. Effectiveness of these parameters as a damage detection tool for
sandwich structure is also assessed
International Journal Of Scientific & Engineering Research Volume 4, Issue 5, May-2013
2013-05-01T00:00:00ZInfluence of Interface Surface Geometries In The Tensile Characteristics Of Friction Welded Joints From Aluminium AlloysNarayanan, K PBaiju, SasidharanArivazhakan, Rhttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/46752014-08-21T20:30:31Z2013-12-01T00:00:00ZInfluence of Interface Surface Geometries In The Tensile Characteristics Of Friction Welded Joints From Aluminium Alloys
Narayanan, K P; Baiju, Sasidharan; Arivazhakan, R
Friction welding is a solid state joining process that produces coalescence in materials, using the
heat developed between surfaces through a combination of mechanical induced rubbing motion and
applied load. In rotary friction welding technique heat is generated by the conversion of mechanical
energy into thermal energy at the interface of the work pieces during rotation under pressure.
Traditionally friction welding is carried out on a dedicated machine because of its adaptability to mass
production. In the present work, steps were made to modify a conventional lathe to rotary friction welding
set up to obtain friction welding with different interface surface geometries at two different speeds and to
carry out tensile characteristic studies. The surface geometries welded include flat-flat, flat-tapered,
tapered-tapered, concave-convex and convex-convex. A comparison of maximum load, breaking load and
percentage elongation of different welded geometries has been realized through this project. The
maximum load and breaking load were found to be highest for weld formed between rotating flat and
stationary tapered at 500RPM and the values were 19.219kN and 14.28 kN respectively. The percentage
elongation was found to be highest for weld formed between rotating flat and stationary flat at 500RPM
and the value was 21.4%. Hence from the studies it is cleared that process parameter like “interfacing
surface geometries” of weld specimens have strong influence on tensile characteristics of friction welded
joints
International Journal of Innovative Research in Science, Engineering and Technology,Volume 2, Special Issue 1, December 2013
2013-12-01T00:00:00ZDezincification of Epoxy Coated Brass in Cochin Estuary, IndiaMathiazhagan, ARani, JosephNarayanan, K Phttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/46712014-08-21T20:30:30Z2010-08-01T00:00:00ZDezincification of Epoxy Coated Brass in Cochin Estuary, India
Mathiazhagan, A; Rani, Joseph; Narayanan, K P
Inhibited α brasses are largely immune to
dezincification in most water, but the effect of tin and arsenic
addition to α/β brasses is not so reliable or predictable in
controlling the problem. There have been many cases of
dezincification in duplex brasses in both fresh water and
seawater. There is no reliable method of inhibiting the
dezincification of two-phase brass despite there are some
protection methods such as inhibitors, electro deposition and
electro polymerization. Organic coatings are effectively used for
the protection of metals due to their capacity to act as a physical
barrier between the metal surface and corrosive environment.
Hence, epoxy coating on brass was applied and effect of this
against dezincification in Cochin estuarine water over a period
of one year was studied and reported in this paper
International Journal of Chemical Engineering and Applications, Vol. 1, No. 2, August 2010
2010-08-01T00:00:00Z