Preparation and thermodynamic analysis of the porous ZrO2/(ZrO2 + Ni) functionally graded bolted joint

Abstract

a b s t r a c tCeramicemetal functionally graded materials (FGMs) have been extensively used in aerospace engineering where high strength and excellent heat insulation materials are desired. In this paper, the thermodynamic behavior of the Thermal Protection System (TPS) used bolted joints made up of porous ZrO 2 /(ZrO 2 þ Ni) FGMs is investigated by finite-element (FE) modeling. The bolted joint is subjected to reentry heating corresponding to the Access to Space Vehicle. Thermodynamic simulations are carried out to yield the transient response of the porous ZrO 2 /(ZrO 2 þ Ni) functionally graded bolted joint (FGBJ). The effects of the preload on the thermomechanical behavior and service reliability of the bolted joint are numerically analyzed in detail by ABAQUS codes. It is found that the preload relaxation of the bolted joint occurs at elevated temperature, and the preload has significant influence on service reliability of the bolted joint under transient thermomechanical circumstances. With the increase of the preload, stress concentration which occurs at the root of the first thread of the bolt increases rapidly and predominates in service reliability. Proper preload is thus defined to balance the service reliability and tightness of the bolted joint. Further studies show that the shape of the nut has a great effect on the stress concentration of the thread, the optimized nut is designed to reduce the stress concentration of the thread, and thus the reliability of the bolted joint is also improved.

Characterization of Aluminum Alloy–Silicon Carbide Functionally Graded Materials Developed by Centrifugal Casting Process

“…Taking into account that an assembly of two or more materials with completely different properties leads to a composite with superior properties surpassing those of each component basic material, we realize why significant amounts are invested in researching these materials. Precisely for this improvement in terms of properties when compared to those of each component, these materials have special applications, for example in the aerospace industry [11][12][13], in the biomedical industry as well as in other engineering applications that require new materials with superior properties.…”

A comparative investigation of hardness and compression strength of Nickel coated B4C reinforced 601AC/201AC selective layered functionally graded materials

“…After the invention of man-made FGMs by the Japanese, the research continued by the different parts of world and now-a-days FGMs have been customized to take the advantages of properties of different materials to fulfil the requirements of different engineering applications like defends, Biomaterials, photocells, nuclear reactors, thermal shields, Cermets, the following literature gives some areas of application proposed by different authors. Zhou et al [7] analysed the model to estimate the thermal residual stresses in a sandwich ceramic FGM of ZrO 2 /ZrO 2 +Ni, which finds the application in aerospace as high temperature resistant screwed fasteners due to its improved stress concentration [8], tensile properties [9] and shear properties [10]. Tawakol Enab [11] proposed total knee replacement joints with FGM tibia tray of Titanium (Ti) and hydroxyapatite (HAP).…”

Progressive Damage Modelling of Transverse Impact Behavior of Adhesively Bonded Composite Joints

“…In recent years, the implementation of adhesives in the joining method of composite materials in structural applications in aeronautics has increased due to the many advantages over the traditional mechanical joints. Mechanical joints using bolts/fasteners have to deal with the potential problems such as unevenly distributed load in threads (Zhou et al, 2015a), stress concentration in threads (Zhou et al, 2015b), shear damage of bolts (Zhou et al, 2016), heat shorts for pure metal bolts or brittle fracture for pure ceramic bolts (Zhang et al, 2014), residual stress for novel metal-ceramic composite bolts (Zhou et al, 2015c;2015d). The use of adhesive bonding comes in conjunction with the establishment of the use of composite materials, as it enables to use them more efficiently.…”