scholarly journals Load distribution in threads of porous metal–ceramic functionally graded composite joints subjected to thermomechanical loading

2015 ◽  
Vol 134 ◽  
pp. 680-688 ◽  
Author(s):  
Wenbin Zhou ◽  
Rubing Zhang ◽  
Shigang Ai ◽  
Rujie He ◽  
Yongmao Pei ◽  
...  
Keyword(s):  
Load Distribution ◽  
Porous Metal ◽  
Functionally Graded ◽  
Composite Joints ◽  
Thermomechanical Loading ◽  
Functionally Graded Composite ◽  
Metal Ceramic

scholarly journals Load distribution in threads of porous metal-ceramic functionally graded composite joints subjected to thermomechanical loading

2019 ◽  
Author(s):  
Wenbin Zhou
Keyword(s):  
Load Distribution ◽  
Thermal Protection ◽  
Space Vehicle ◽  
Porous Metal ◽  
Functionally Graded ◽  
Service Reliability ◽  
Bolted Joint ◽  
Modulus Ratio ◽  
Total Load ◽  
Metal Ceramic

Metal-ceramic functionally graded materials (FGMs) have been extensively used in aerospace engineering where high strength and excellent heat insulation materials are desired. In this paper, load distribution in threads of the Thermal Protection System used bolted joint made up of porous ZrO2/(ZrO2+Ni) FGMs is investigated by ABAQUS codes. The bolted joint is subjected to reentry heating corresponding to the Access to Space Vehicle. Effects of bolt-nut parameters including thread tooth profile, thread pitch, and modulus ratio of bolt to nut on load distribution in threads are analyzed in detail. It is found that uneven load distribution in threads occurs at elevated temperature, which mainly focuses on the first two threads closest to the nut bearing surface, with the first thread carrying 74% of the total load. Bolt-nut parameters have great effects on load distribution in threads, with trapezoidal thread, extra fine thread and greater modulus ratio of bolt to nut leading to more evenly distributed load. Further studies show that nut shape has significant effects on load distribution in threads, the optimized nut is designed to make the maximum load bearing ratio of the thread decrease to 30.21%, and thus the service reliability of the bolted joint is greatly improved.

A RADIATION SENSITIVE ADHESIVE SYSTEM FOR FUNCTIONALLY GRADED COMPOSITE JOINTS

2021 ◽  
Author(s):  
SAMUEL B. HURVITZ ◽  
SCOTT STAPLETON ◽  
JAMAL HUSSEINI
Keyword(s):  
Adhesive Bond ◽  
Adhesive System ◽  
High Energy ◽  
Bond Line ◽  
Functionally Graded ◽  
Composite Joints ◽  
Stress Concentrations ◽  
Functionally Graded Composite ◽  
Bonded Composite ◽  
Radiation Sensitizer

Adhesively bonded composite joints can help reduce weight in structures and avoid material damage from fastener holes, but stress concentrations formed at the edges of the adhesive bond line are a main cause of failure. Stress concentrations within the adhesive can be reduced by lowering the stiffness at these edges and increasing the stiffness in the center of the joint. This may be achieved using a dual-cure adhesive system, where conventional curing is first used to bond a lap joint, after which high energy radiation is applied to the joint to induce additional crosslinking in specific regions. Anhydride-cured epoxy resins have been formulated to include a radiation sensitizer enabling the desired cure behavior. Tensile testing was performed on cured systems containing varying levels of radiation sensitizer in order to evaluate its effects on young’s modulus as a function of radiation dose.

Thermal Post-Buckling Analysis of Functionally Graded Composite Plates with Nonlinear Aerodynamic Forces

2010 ◽  
Vol 123-125 ◽  
pp. 280-283
Author(s):  
Chang Yull Lee ◽  
Ji Hwan Kim
Keyword(s):  
Material Properties ◽  
Numerical Solutions ◽  
Virtual Work ◽  
Shear Deformation Theory ◽  
Composite Plates ◽  
Buckling Analysis ◽  
Functionally Graded ◽  
Governing Equations ◽  
Functionally Graded Composite ◽  
Post Buckling

The post-buckling of the functionally graded composite plate under thermal environment with aerodynamic loading is studied. The structural model has three layers with ceramic, FGM and metal, respectively. The outer layers of the sandwich plate are different homogeneous and isotropic material properties for ceramic and metal. Whereas the core is FGM layer, material properties vary continuously from one interface to the other in the thickness direction according to a simple power law distribution in terms of the volume fractions. Governing equations are derived by using the principle of virtual work and numerical solutions are solved through a finite element method. The first-order shear deformation theory and von-Karman strain-displacement relations are based to derive governing equations of the plate. Aerodynamic effects are dealt by adopting nonlinear third-order piston theory for structural and aerodynamic nonlinearity. The Newton-Raphson iterative method applied for solving the nonlinear equations of the thermal post-buckling analysis

Three-Dimensional Parametric Finite-Volume Homogenization of Periodic Materials with Multi-Scale Structural Applications

2018 ◽  
Vol 10 (04) ◽  
pp. 1850045 ◽  
Author(s):  
Qiang Chen ◽  
Guannan Wang ◽  
Xuefeng Chen
Keyword(s):  
Finite Volume ◽  
Three Dimensional ◽  
Functionally Graded ◽  
Attractive Alternative ◽  
Matrix Assembly ◽  
Functionally Graded Composite ◽  
Multi Scale ◽  
Hexahedral Elements ◽  
Stiffness Matrices ◽  
Structural Applications

In order to satisfy the increasing computational demands of micromechanics, the Finite-Volume Direct Averaging Micromechanics (FVDAM) theory is developed in three-dimensional (3D) domain to simulate the multiphase heterogeneous materials whose microstructures are distributed periodically in the space. Parametric mapping, which endorses arbitrarily shaped and oriented hexahedral elements in the microstructure discretization, is employed in the unit cell solution. Unlike the finite-element (FE) technique, the expressions for local stiffness matrices are derived explicitly, enabling efficient global stiffness matrix assembly using an easily implementable algorithm. To demonstrate the accuracy and efficiency of the proposed theory, the homogenized moduli and localized stress distributions produced by the FE analyses are given for comparisons, where excellent agreement is always obtained for the 3D microstructures with different geometrical and material properties. Finally, a multi-scale stress analysis of functionally graded composite cylinders is conducted. This extension further increases the FVDAM’s range of applicability and opens new opportunities for pursuing other areas, providing an attractive alternative to the FE-based approaches that may be compared.

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