Systematic Approach to Optimize Injection Molding and Microstructural Analysis of Fiber Reinforced Resins for Anisotropic Mechanical Characterization

Fiber reinforced resin materials are increasingly being used in aviation, automotive, mass transportation and healthcare industries. Engineers are keen to explore new design concepts with such materials, since these materials promises to offer high strength to weight ratio, elimination of secondary operations and ease in process ability to form complex shaped parts through injection molding. The mechanical properties of molded parts made from such materials depends on the orientation of the reinforcing fibers. Such orientation occurs in fiber-reinforced plastics, since the fibers in the plastic melt during processing, will orient in different directions under the influence of shear forces that are driven by flow pattern. This paper provides details on systematic and abusive injection molding of test specimens and characterizing anisotropic mechanical data that can be used for fiber orientation predictions in computer aided engineering programs. Systematic molding as compared to abusive molding, identifies optimum molding parameters that reduces part–to-part variation during injection molding, thereby reduces part rejections. It provides optimum part performance during application and the process settings are repeatable and reproducible. The intention of this paper is to share widely such a method to make this process less of a skill or art. The mechanical properties covered here are elastic, shear modulus and poisson ratio. Scanning electron microscopy (SEM) analysis revealed that most of the fibers are aligned in melt flow direction for systematic molded plaques, leading to higher stiffness and strength characteristics as compared to transverse to melt flow.

ICE CRYSTAL DYNAMICS IN THE NANOCOMPOSITE NETWORKS

Water is abundant in every day's life and critically useful in many biological systems and in water-based mechanical devices. Freeze-thaw process is one of the inevitable dynamics especially for the materials working at sub-zero conditions where ice crystal changes the physical property of the whole crystal-embedded composite systems. However, still many phenomena have not been explained in terms of crystal control methodology in conjunction with mechanical properties. In this study, ice crystal dynamics occurring in network systems has been discussed. Small size of network structure contributes to crystal growth inhibition especially time-dependent recrystallization. This could be explained by nano-scale confinement effect at the initial nucleation/growth stage, controlling size and shape of ice crystallites. The physical property of crystal embedded-nanocomposite is dominated by ice crystal behaviors over the network. This includes freezing point depression, frequency-dependent and temperature-dependent storage modulus changes and cooling rate- dependent dynamics. This study sheds light on ice crystal control methodology which would be useful in various materials and machines working under freeze-thaw dynamics.

Influence of cyclic cylinder pressure variability in the numerical transfer path analysis of multi-body engine

Practical mechanical systems often operate with some degree of uncertainty. The uncertainties can result from poorly known or variable parameters, from uncertain inputs or from rapidly changing forcing that can be best described in a stochastic framework. In automotive applications, cylinder pressure variability is one of the uncertain parameters that engineers have to deal with when designing and analyzing internal combustion engines. Multi-body dynamics is a powerful numerical tool largely implemented during the design of new engines. In this paper the influence of cylinder pressure cyclic variability on the results obtained from the multi-body simulation of engine dynamics is investigated. Particular attention is paid to the influence of these uncertainties on the analysis and the assessment of the different engine vibration sources. A numerical transfer path analysis, based on system dynamic sub structuring is used to derive and assess the internal engine vibration sources. In order to investigate the cyclic variability of cylinder pressure, a Monte Carlo approach is adopted. Starting from measured cylinder pressure that exhibits cyclic variability, random Gaussian distribution of the equivalent force applied on the piston is generated. The aim of this paper is to outline a methodology which can be used to derive correlations between cyclic variability and statistical distribution of results. The statistical information derived can be used to advance the knowledge of the multi-body analysis and the assessment of system sources when uncertain inputs are considered.

Experimental Estimation of Inertia Tensor and Centre of Gravity of a Mini Helicopter

This paper describes the experimental estimation of the mini-helicopter inertia and center of gravity (CG) location. A three degree of freedom inertia test rig and an Inertia Measurement Unit (IMU) were used to measure the oscillation frequencies about three axes under different configurations. These frequency data are then manipulated to estimate the inertia tensor and CG location of the mini-helicopter model.

Insight Natural Vision Processing like Engineering for Machine Vision

Artificial Vision or Computer vision or machine vision are the terms which maximum authors defined as Vision for calibration, inspection, error detection and correction, quality check or anything else all process electronically and engineering based on Natural human which is unique. Hence with this sense simply term is Vision Engineering, because Artificial, Computer or Machine all designed electronically with similarities. I have shown in my modeling with help of two models how we can engineer it.

Performance Study of a DC Refrigerator Powered by Different Solar PV Modular Sets: paper II.

This study exhibits the performance of a DC domestic use refrigerator. Sixty Watts rated power unit was used. Two PV sources of solar electricity power of 100 Wp and 70 Wp modules. A battery of 12 V and 21 Ah, was connected to the cycle. The experiments were carried out using five different conditions for the power connection: The battery was used in different conditions as follows: standalone full charged; either initially full charge or completely discharged and connected with either one of the module generator. Five experiments with different combinations in the connection conditions of the battery and the modules. The on/off sequence effect on the performance of: Te; Tc and, TL were mainly monitored. In this study, it was required to study the lowest solar power supply condition that may be unsuitable to sustain continuous operation. This helps generators designers and conserves energy. Acceptable performance was reached in four experiments. The fifth experiment was with initially completely discharged battery with the 70 W. module, gave continuous cyclic on/off which is an unacceptable performance.