ABSTRACT Distortion is the main problem of welding industry. This problem can be solved by variety of techniques such as heat sinking and side heating. During the heating and cooling cycle thermal strains occurs in the weld and adjacent area. The strains produced during the heating stage of welding are always accompanied by plastic deformation of the metal. The stresses resulting from these strains combine and react to produce internal forces that cause a variety of welding distortions.
Split Hopkinson pressure bar Aim and objectives of work Split Hopkinson pressure bar in most versatile apparatus for regulating the active behaviour of materials. To get a simple FEM of SHPB and numerical analysis was borne away in the present investigation and to simulate dynamic compression response based on quasi-static test to amount the mechanical response at high line rates and examine the dynamic compression properties, i.e. energy absorption and compressive force at advanced strain rates, to improve full scales stress-strain curves at altered strain rates and to examine the strain rate behaviour of differing materials. Modelling and test various geometries of specimens. Compare the experimental value with numerical test result values.
One of the most important features in surface roughness is intricate fabricated components using Additive Manufacturing. The Reduction and optimizing of surface roughness is belong to process conditions and input parameters. Selective laser Melting and Electron Beam Melting are the process used in Additive manufacturing technique to improve the surface quality of the material component. In surface Roughness, achieving for meeting the specifications or improving the properties, by means of surface quality, geometric dimensional accuracy and mechanical properties of the materials. The common value of the surface roughness for SLM process is varying between 15(micrometre) to 40(micrometre).
Small overload region and large fatigue region associated with multiple ratchet marks on the fracture surface indicates that the load was light but there were high stress concentration at the crack initiated region. 2. Chemical Analysis revealed that the pull rod material conformed to EN 10083-2 grade 30CrNiMo8, as specified by the customer. 3. Unbroken dendritic structure resulted in segregation at inter- dendritic region and other anomalies such as blow holes, inclusions resulted in hardness difference across the cross section of pull rod.
They showed when the aspect ratio of plate or the thickness to span ratio increased, the critical buckling temperature difference increased. In recent years, researchers for reinforcement of composites and FG plates used in engineering structures embedded nano tubes, shape memory alloy (SMA), electrorheological fluids, smart materials–piezoelectric materials, etc. Park et al.  investigated vibration of thermally post-buckled composite plates embedded with shape memory alloy fibers with simply supported boundary conditions based on the start-order shear deformation plate theory and nonlinear finite element method. The thermal post-buckling deflection was determined based on Newton–Rapson method.
The generated oscillations from the applied electrical power at high frequency of the order of 20 kHz to the piezoelectric transducer. The oscillations produced by the transducer are very small, so a booster is connected to the transducer in order to increase the amplitude of vibration . Thus produced mechanical vibration is then transferred to the metal horn which induces ultrasonic sound waves. This energy is used for welding the components. A high quality weld can be obtained through ultrasonic welding even at a larger relative distance from the site from where the mechanical vibrations are introduced.
All of the processes are viable ways to join two similar or dissimilar metals, each with its own advantages and disadvantages including equipment, size and shape of material to be welded, temperature ranges, welding times and relevant applications. The common techniques (in brief) are: a) Roll bonding – creates a weld between two or more sheets or plates, in intimate contact, by sending them through a rolling mill, which will cause severe plastic deformation that results in bonding. b) Diffusion bonding – is a process by which a joint can be achieved between similar and dissimilar metals, by the diffusion of atoms across the interface, based on the bonding pressure and heat applied over time. Temperature should be from 0.5 to 0.8 of the melting point of the most fusible metal. c) Ultrasonic welding – is a solid-state process where a joint is formed through the use of vibratory energy.
Literature review A number of researchers have tried theoretically or experimentally the ways to predict the welding distortions and welding residual stresses. Some of them have also tried to predict the thermal and mechanical responses of welding structure in practice industrial production. Two dimensional non linear transient welding simulations with three dimensional structural analyses in a decoupled approach. Using two dimensional thermo mechanical welding process simulations for determining the temperature loading for a three dimensional structural model determine buckling distortion after welding in large and complex structures. The simplified FEM to simulate out of plane distortion caused by fusion butt welding; he replaced the thermal
Hertz contact stress theory allows for the prediction of the resulting contact area, contact pressure, compression of the bodies, and the induced stress in the bodies. 2.1 Analysis of surface and sub-surface cracks due to fatigue D. Finney Charles, R. Gnanamoorthy (2010) investigated rolling contact fatigue (RCF)
The destructive and semi destructive techniques, called also mechanical method. Mechanical methods are stress relaxing methods. These methods relay on the measurement of deformations due to the release of residual stresses upon removal of material from the specimen. Sectioning, contour, hole-drilling, ring-core and deep-hole are based on destructive and semi destructive techniques used to measure residual stresses in structural members. Non-destructive methods include X-ray or neutron diffraction, ultrasonic methods and magnetic methods.