Fracture life estimation of Al-1050 thin beams using empirical data and a numerical approach

A technique based on empirical data and finite element (FE) analysis to predict the fracture life of Al-1050 beams with the help of its fundamental mode is presented in this study. Experiments were performed on a non-prismatic beam vibrating with a constant value of the amplitude at the fixed end until the complete fracture of the specimen was achieved. The beam was vibrating at its fundamental mode to achieve fracture in less time. A power law model was used to acquire the possible trends between the values of natural frequencies and the number of cycles recorded during these experiments. These trends were further compared with a numerically modelled specimen but with artificial cracks. FE modal analysis was used for this comparison. An error of less than 1% was observed in the estimated number of total cycles obtained through the power law model before fracture, compared to those obtained using the numerical approach. Using this approach, the fracture life was also predicted for specimens of different lengths

Effect of hybrid reinforcement on the performance of filament wound hollow shaft

Previous studies have shown that composite materials can replace metals as the material of construction in shafts. Composite material shafts are normally made up of polymer matrix composites as they are easy to design and economical to manufacture. This paper investigates the effect of hybrid reinforcement on the performance of filament wound hollow shaft. The hybrid shafts are composed of hybrid filaments including a combination of carbon, glass and aramid fibers. The initial stage involved development and verification of FEA model in order to establish grounds for further experimentation. Afterwards, a design of experiments model was established and experiments were performed using FEA. After the design phase, the shafts were manufactured using filament winding processing technique employing suitable matrix and reinforcement systems. Lastly, the shafts were tested for torsional characteristics, hardness, density and chemical reactivity. The results showed that carbon fiber reinforcement shows best results in terms of torsional characteristics. In terms of chemical reactivity, carbon-glass hybrid reinforcement exhibited minimum degradation. Furthermore, it was also found that hybrid reinforcements containing carbon-aramid fibers showed better results in terms of density and surface hardness

Does Celebrity Endorsement Influence the Corporate Loyalty: Mediating Role of Corporate Credibility?

Celebrity endorsement in product marketing and advertising is one of the most important factors in companies’ promotion strategies. Celebrities as one of the major tools in advertising can lead to encouraging consumers to use specific products and corporate loyalty because of their special and unique abilities or characteristics. The purpose of this study is to examine the effect of celebrity endorsement on corporate loyalty by concentrating on the mediating role of corporate credibility. Questionnaire survey method was adopted for data collection and data have been collected by applying simple random sampling technique. Study result revealed that the celebrity endorsement has a positive effect on corporate credibility and corporate loyalty. Moreover, corporate credibility has a positive effect on corporate loyalty. Moreover, corporate credibility significantly mediates the relationship between celebrity endorsement and corporate loyalty. At the end of this article, obstruction of this study, implementation, and outlines for another research also provided

Effect of carbon fiber winding layer on torsional characteristics of filament wound composite shafts

Composite materials are promising candidates as structural materials and substituting metals in extensive applications. Shafts are used in aerospace and automotive structures and hence replacing conventional shafts with composite material shafts is a viable option. Hollow shafts can be manufactured using filament winding technology employing hoop and helix winding layers. Filament winding technology offers several advantages such as continuous filaments through structure and capability for continuous manufacturing. Previously researchers have investigated composite shafts; however, this research elaborates the significance of type of winding layer on torsional characteristics. This paper reports the effects of carbon fiber winding layer on torsional characteristics of filament wound composite hollow shafts. Shafts were manufactured using filament winding technology with continuous carbon fiber roving and epoxy matrix material and tested using the torsional testing machine. The finite element (FE) simulations have been carried out with a general purpose commercial FE code, ABAQUS, to demonstrate shafts in torsional loading. The results revealed that values from torsional test correlate with developed finite element model. It was concluded that helix winding layer offers high hardness and more resistance to torsional forces as compared to hoop winding layer in filament wound composite shafts

Surface analysis of conversion coating of ASTM A 516

Surface engineering is a vital aspect of manufacturing industries owing to its benefits both in surface protection and aesthetics. It has been extensively used in various industries to guard against corrosion which is a naturally occurring and highly undesirable phenomenon. Present research has endeavored to analyze protection of ASTM A516 (Grade 70) from corrosion through surface engineering. Different methods of surface treatment and conversion coating were carried out to efficiently enhance corrosive protection. Comparative analysis of various samples was conducted to analyze their ability to resist corrosion. Samples with surface treatment followed by conversion coating were found to be effective even against 0.7% aqueous sulfuric acid with no significant cracks in the coating layer. On the other hand, conversion coated only samples showed protection against 0.35% acid. The coating of conversion coated only samples was found to have gaps/ cracks as indicated by 3% Cupric Sulfate whereas no such gaps were found in surface treated samples. Optical microscopy identified a more uniform coating thickness for surface treated samples in comparison with conversion coated only samples. In depth morphology analysis using SEM highlighted that surface treated samples had low porosity preventing the corrosion elements to reach the substrate thereby implementing higher corrosion potential

A methodology for flexibility analysis of pipeline systems

Pipeline systems serve a crucial role in an effective transport of fluids to the designated location for medium to long span of distances. Owing to its paramount economic significance, pipeline design field have undergone extensive development over the past few years for enhancing the optimization and transport efficiency. This research paper attempts to propose a methodology for flexibility analysis of pipeline systems through employing contemporary computational tools and practices. A methodical procedure is developed, which involves modeling of the selected pipeline system in CAESAR II followed by the insertion of pipe supports and restraints. The specific location and selection of the inserted supports is based on the results derived from the displacement, stress, reaction, and nozzle analysis of the concerned pipeline system. Emphasis is laid on the compliance of the design features to the leading code of pipeline transportation systems for liquid and slurries, ASME B31.4. The discussed procedure and approach can be successfully adjusted for the analysis of various other types of pipeline system configuration. In addition to the provision of systematic flow in analysis, the method also improves efficient time-saving practices in the pipeline stress analysis

Novel selective feeding scheme integrated with SPDT switches for a reconfigurable bandpass-to-bandstop filter

This paper demonstrates a new technique for designing high performance reconfigurable bandpass-to-bandstop filters by employing a ring resonator and a selective feeding scheme integrated with single-pole double-throw switches (SPDT). The transformation from bandpass-to-bandstop mode and vice-versa is achieved by connecting or disconnecting two\lambda g/4 open-circuited stubs on the ring using PIN diodes. SPDT switches are employed for electronic switching between two different feeding line sections. In the bandpass state the resonator presents two transmission zeros near the edges of the passband and four attenuation poles inside the passband, enhancing the filter's performance, thus achieving excellent sharp rejection with high roll-off-rate (ROR20dB). On the other hand, high stopband rejection with wide bandwidth, good return loss and good skirt-band attenuation rates are achieved in the bandstop state. Even-and odd-mode analysis is adopted and closed-form expressions are derived to describe the filter's behaviour. To verify the validity of the proposed design, a prototype filter was fabricated and measured. In measurement, a 65% 3-dB bandwidth bandpass filter (BPF) with an insertion loss of 0.86 dB was switched to a 70% 20-dB bandwidth bandstop filter (BSF) with more than 40 dB stopband rejection

A projected finite element update method for inverse identification of material constitutive parameters in transversely isotropic laminates

In this paper, a novel application of Finite Element Update Method (FEUM) is proposed for the inverse identification of material constitutive parameters in transversely isotropic laminates. Two-dimensional Digital Image Correlation (2D–DIC) is used for full-field measurements which is required for the identification process. Instead of measuring the in-plane displacements, which is a well-known application of 2D–DIC, we seek to measure the pseudo-displacements resulting from out-of-plane (towards camera) deflection of plate under a point load. These pseudo-displacements are basically the perspective projection of the three dimensional displacement fields on the image-plane of the image acquisition system. The cost function in this method is defined in terms of these projections instead of the true displacements – and hence the name Projected Finite Element Update Method (PFEUM). In this article, identification of in-plane elastic moduli of Carbon Fiber Reinforced Plastic (CFRP) plate has been performed using plate bending experiments which show pre-dominantly out-of-plane deflection with little contribution from the in-plane displacements. Identification results are validated by direct experimental measurements of the unknown elastic constants as well as theoretical estimates based on volume ratio of constituents. The results show good conformance between estimated and target values for at least three material parameters namely E1, E2 and G12. Effects of experimental noise on parameter estimates has also been evaluated to explain the observed deviation in estimated parameters with current test configuration

A Novel Application of Quantum Speed Limit to String Theory

In this work, we investigate the implications of the concept of quantum speed limit in string field theory. We adopt a novel approach to the problem of time on world-sheet based on Fisher information, and arrive at a minimum time for a particle state to evolve into another particle state. This is done using both the Mandelstam-Tamm bound and the Margolus-Levitin bound. This implies that any interaction has to be smeared over such an interval, and any interaction in the effective quantum field theory has to be non-local. As non-local quantum field theories are known to be finite, it is expected that divergences should be removed from effective quantum field theories due to the quantum speed limit of string theory.Comment: 9 page