Application of functionally graded materials (FGMs) in energy, aviation and nuclear industries has increased since the last decade due to potential reduction of in-plane and transverse through-the-thickness stresses, enhanced residual stress distribution, superior thermal properties, free from delamination, and reduced stress intensity factors. FGMs are categorized as an advanced class of composite materials where the two constituent materials are graded along the thickness direction. Absence of sharp change in material property in the interface layer eliminates the problem of delamination and debonding, which is a major concern for traditional composite material. In this work, PLA-ABS functionally graded material is manufactured using additive manufacturing techniques through fused deposition modeling (FDM) using Y-type extruder. X-ray computed tomography test is conducted to see the air void (generated during printing) distribution in the printed FGM. Tensile test (as per ISO-527standrad) is conducted to evaluate the Young’s Modulus of additive manufactured FGMs. Three different measuring positions are considered in the FGM specimens to check the effect of property change along the grading direction. Tensile test results of PLA-ABS FGM are compared with their individual constituents (ABS and PLA). Further, flexural vibration test is conducted to evaluate the natural frequency of printed FGM beam. Experimentally determined mechanical and dynamic characteristics in terms effective Young’s Modulus and natural frequency are analyzed and discussed.

Functionally graded material (FGM) is an advanced class of composite material. In FGM, the volume fraction of each constituent can be tailor-made across the thickness for desired applications. In this paper, the analytical solution and numerical simulation of free vibration and transient heat conduction problem in a functionally graded pipe are considered. 3D elasticity theory is adopted for considering the thickness effect in the natural frequency derivation. For solving the transient heat conduction problem in FG pipe, the extended shifting variable method is used. A multi layer model is considered to numerically simulate the vibration and transient heat conduction behavior of FG pipe using standard finite element method package. Results obtained from both analytical solution and numerical simulations are compared for the free vibration and transient heat conduction. The 8-and 16-layer models show the higher accuracy for simulating FG pipe. For 16-layer model, the difference in natural frequency between numerical results and analytical solution is under 0.18%. The transient temperature distribution at specific position of the FG pipe is obtained from transient heat conduction study for various FG power law indices. The free vibration and transient temperature distribution of the FG pipe will help to tailor the FG pipe by adjusting the graded ways for specific application.

No abstract

No abstract

Functionally graded materials (FGMs) are advanced class of composite materials which can be used as the thermal barrier to protect inner components from the outside high temperature environment. In FGMs, the volume fraction of each constituent can be tailored made across the thickness for desired applications. In this work, the simulation of FGMs in pipes is considered. Despite the wide application of pipes in machinery, those pipes would suffer from many safety problems, such as thermal stress, cavitation, fracture etc. Application of FGMs to the piping systems could lead to some new solutions accounting for safety measures and higher service life. However, the complex phenomena within the fluid structure interaction are hard to describe with the theoretical solution. The visualization of results from simulation will be helpful in understanding the distribution of kinds of physical quantities within the concerned model. For the simulation, FGMs are modeled as the layered structure in the standard finite element method (FEM) package based on FGM constituent law. The free vibration of the FG pipe is simulated and the accuracy of layered model is verified by numerical calculations. Further, based on the layered model, conjugate heat transfer simulations in a heat exchanger with FGMs are conducted.