Use of Neural Network Based Prediction Algorithms for Powering Up Smart Portable Accessories

Neural Processing Letters - Emerging Trends in the use of smart portable accessories, particularly within the context of the Internet of Things (IoT), where smart sensor devices are employed for...     

Liquid metal corrosion of 316L,Fe<Subscript>3</Subscript>Al,and FeCrSi in molten Zn-Al baths

Corrosion tests of 316L and two intermetallic compounds Fe₃Al and FeCrSi in industrial Galvanizing (Zn-0.18Al), GALFAN (Zn-5Al), GALVALUME (Zn-55Al), and Aluminizing (Al-8Si) baths and lab-scale static baths were conducted. In on-line tests in industrial hot-dip baths, 316L steel shows better corrosion resistance than Fe₃Al in Galvanizing, GALFAN, and GALVALUME baths. The corrosion resistance of 316L and Fe₃Al is similar in Aluminizing bath. In static tests, FeCrSi shows the best corrosion resistance in pure Zn, Zn-55Al, and Al-8Si baths. The corrosion resistance of 316L is better than that of Fe₃Al. In Zn-5Al bath, 316L shows no thickness loss after the test. For the same bath composition, the corrosion rates of the alloys in industrial baths are higher than those in static baths. Bath temperature and chemical composition play important roles in corrosion and intermetallic layer formation. Increasing bath temperature accelerates the corrosion process and changes the nature of intermetallic layers. A small amount of aluminum reduces the corrosion process by reducing the activity of Zn and forming inhibition layer. However, after aluminum content reaches the critical point, the dominant corrosion process changes from Zn-Fe reaction to Al-Fe reaction, and, consequently, the corrosion process accelerates by increasing aluminum content in the bath.     

Prediction of Buckling-Mode Interaction in Composite Columns

Pultruded structural shapes are often used as columns of intermediate length, for which the global and local buckling loads are close. Interaction between the two buckling modes is accounted for in design by an empirical interaction constant. Theoretical/numerical prediction of such a constant is presented in this article. Stability theory is used to demonstrate the existence of buckling-mode interaction. The continuation method is used to study the imperfection sensitivity of the columns. A relationship between column imperfection and the interaction constant is established. Experimental results are presented to support the analysis.     

A mechanistic model for transverse damage initiation,evolution, and stiffness reduction in laminated composites

A constitutive model to predict stiffness reduction due to transverse matrix cracking is derived for laminae with arbitrary orientation, subject to in-plane stress, embedded in laminates with symmetric but otherwise arbitrary laminate stacking sequence. The moduli of the damaged laminate are a function of the crack densities in the damaging laminae, which are analyzed one by one. The evolution of crack density in each lamina is derived in terms of the calculated strain energy release rate and predicted as function of the applied load using a fracture mechanics approach. Unlike plasticity-inspired formulations, the proposed model does not postulate damage evolution functions and thus there is no need for additional experimental data to adjust material parameters. All that it is needed are the elastic moduli and critical energy release rates for the laminae. The reduction of lamina stiffness is an integral part of the model, allowing for stress redistribution among laminae. Comparisons with experimental data and some results from the literature are presented.     

Beyond plain weave fabrics – I. Geometrical model

In response to the large variety of weaving styles offered by the textile industry, a new general approach for the geometrical modeling of 2D biaxial orthogonal woven fabric reinforcements for composite materials is proposed here. New geometrical parameters are introduced in order to describe general families of twill and satin woven patterns, and a new classification of woven fabrics is proposed based on these parameters. Generation of the 3D internal geometry of the woven fabric families is achieved based on new geometrical functions that consider the actual configuration of the composite material in all its complexity. The proposed geometrical model is intended as the foundation for further analytical or numerical modeling of the mechanical properties of the composite materials reinforced with these fabrics.     

A phenomenological design equation for FRP columns with interaction between local and global buckling

A design equation for fiber reinforced plastic columns is presented in this paper, based on the interaction between local (flange) and global (Euler) buckling observed during testing of the FRP columns included in this investigation. An existing interaction equation is adapted to account for the modes of failure observed in columns made of fiber reinforced composite materials. Experimental data generated during this investigation are presented and used to validate the interaction equation and to obtain the interaction constant. A slenderness ratio is proposed and used to present a plot of buckling for all sections and column lengths (short, long, and intermediate). An expression for the optimum column length to be used in the experimental determination of the interaction constant is proposed.     

Beam-Column Design Equations for Wide-Flange Pultruded Structural Shapes

A simple procedure is developed for the selection of pultruded structural shapes to be used as beam-columns in structural design. The design equations are then validated by comparison with experimental data gathered during beam-column testing of wide-flange and I-beam pultruded structural shapes. The design procedure accounts for axial load eccentricity and bending action induced by lateral loads and end-moments. The design equations are set in the context of load and resistance factor design, considering both strength and serviceability. This paper addresses the methodology to determine the resistance factors, which should be used with properly selected load-factors accounting for the variability and uncertainty of the loads. The design equations use section-properties, such as the bending stiffness (EI), which must be measured and supplied by industry. It is found that the section-properties used in the design of beams and columns are sufficient for the design of beam-columns. Therefore, the cost and time involved in testing structural shapes are minimized. This paper also addresses the means by which section-properties can be generated effectively and inexpensively.     

Performability analysis of cloud computing centers with large numbers of servers

The ability to deliver acceptable levels of quality of service is crucial for cloud systems, and this requires performance as well as availability analysis. Existing modeling attempts mainly focus on pure performance analysis; however, the software and hardware components of cloud infrastructures may have limited reliability. In this study, analytical models are presented for performability evaluation of cloud centers. A novel approximate solution approach is introduced which allows consideration of large numbers of servers. The challenges for analytical modeling of cloud systems mentioned in the literature are considered. The analytical models and solutions, therefore, are capable of considering large numbers of facility nodes typically up to orders of hundreds or thousands, and able to incorporate various traffic loads while evaluating quality of service for cloud centers together with server availabilities. The results obtained from the analytical models are presented comparatively with the results obtained from discrete event simulations for validation.