Analysis of syntactic foam – GFRP sandwich composites for flexural loads
The use of glass microballoon (GMB) — epoxy syntactic foams as a sandwich core material is studied. The skins and foam core are fabricated and joined instantaneously unlike the procedures followed in the previous studies. Each successive layer of the sandwich is fabricated when the previous layer is in a semi-gelled state. These sandwich samples are characterized for their properties under flexural loading. The failure modes and mechanical properties are carefully investigated. The change in fabrication technique results in a significant increase in the load bearing pattern of the sandwich. In earlier studies, debonding was found to occur prematurely since the bonding between the skins and core is the weakest plane. Using the current technique, core cracking occurs first, followed by skin fiber breaking and debonding happens at the end. This ensures that the load carrying phase of the structure is extended considerably. The sandwich is also analytically studied using Reddy’s higher order shear deformation theory. A higher order theory is selected as the sandwich can no longer be considered as a thin beam and thus shear effects also need to be considered in addition to bending effects.
Review and assessment of various theories for modeling sandwich composites
In this paper, an attempt has been made to analyze and assess the various kinematics and theories used for the modeling of sandwich composites. Major classes of representative theories such as classical laminate theory (CLT), first-order shear deformation theory (FSDT) and high-order theories (HOTs) as well as Zig-Zag based theory models have been considered and a unified kinematic formulation is then proposed. Comparative studies with a finite element solution free of any kinematics assumptions have been conducted to address the applicability and the efficiency of previously considered models and theories. Qualitative and quantitative assessments of displacement, stress fields and modal parameters (natural frequency and loss factor) have been presented and discussed for several geometrical and mechanical sandwich beams configurations as well as a clear picture on suitable applications of each analyzed model.
Research on velocity distribution in semi-dry flue gas desulfurization tower
As an accurate high-quality instantaneous measurement technology, particle image velocimetry (PIV in acronym) has applied widely in single-phase flow and multiphase flow. The velocity distribution in semi-dry FGD tower directly influences gas-solid mix and contact situation. In base of the tower, gas-solid two-phase flow field is more complex, and has the quite tremendous influence to the overall system desulphurization efficiency. This paper utilized PIV to study velocity distribution in Semi-dry flue gas desulfurization tower and obtained velocity distribution.