Nondestructive testing (NDT) techniques in the measurement of residual stresses in composite materials: An overview

Shokrieh, M.M.; Mohammadi, Amir H.

doi:10.1016/b978-0-12-818817-0.00016-0

Cited by 8 publications

(6 citation statements)

References 163 publications

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“…A complementary theoretical study should be devoted in the future to investigate new materials [72][73][74][75][76][77][78][79][80][81], and functionalized multi-layered targets with better performances, keeping the thermo-mechanical stability as the beam spot size is reduced and the intensity of the source increased, that is the current challenge in the muon collider.…”

Section: Discussionmentioning

confidence: 99%

Theoretical Modeling for the Thermal Stability of Solid Targets in a Positron-Driven Muon Collider

Cesarini

Antonelli

Anulli³

et al. 2021

Int J Thermophys

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A future multi-TeV muon collider requires new ideas to tackle the problems of muon production, accumulation and acceleration. In the Low EMittance Muon Accelerator concept a 45 GeV positron beam, stored in an accumulation ring with high energy acceptance and low angular divergence, is extracted and driven to a target system in order to produce muon pairs near the kinematic threshold. However, this scheme requires an intensity of the impinging positron beam so high that the energy dissipation and the target maintenance are crucial aspects to be investigated. Both peak temperature rises and thermomechanical shocks are related to the beam spot size at the target for a given material: these aspects are setting a lower bound on the beam spot size itself. The purpose of this paper is to provide a fully theoretical approach to predict the temperature increase, the thermal gradients, and the induced thermomechanical stress on targets, generated by a sequence of 45 GeV positron bunches. A case study is here presented for Beryllium and Graphite targets. We first discuss the Monte Carlo simulations to evaluate the heat deposited on the targets after a single bunch of 3 × 1011 positrons for different beam sizes. Then a theoretical model is developed to simulate the temperature increase of the targets subjected to very fast sequences of positron pulses, over different timescales, from ps regime to hundreds of seconds. Finally a simple approach is provided to estimate the induced thermomechanical stresses in the target, together with simple criteria to be fulfilled (i.e., Christensen safety factor) to prevent the crack formation mechanism.

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Section: Discussionmentioning

confidence: 99%

Theoretical Modeling for the Thermal Stability of Solid Targets in a Positron-Driven Muon Collider

Cesarini

Antonelli

Anulli³

et al. 2021

Int J Thermophys

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“…Heating the copper sample from 30 to 380 • C resulted in permanent prolongation by 0.06% after the first dilation run (Figure 6). This could be attributed to the presence of Cu 2 O of micrometer size in the copper structure, due to the presence of oxide on the surface of the copper particles before HIPing [36]. Comparison of the CTE values from the first and the second runs pointed to the effective release of residual tensions during the first heating.…”

Section: Thermal Propertiesmentioning

confidence: 98%

Structure and Thermal Expansion of Cu−90 vol. % Graphite Composites

Opálek

Emmer²,

Čička³

et al. 2021

Materials

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Copper–graphite composites are promising functional materials exhibiting application potential in electrical equipment and heat exchangers, due to their lower expansion coefficient and high electrical and thermal conductivities. Here, copper–graphite composites with 10–90 vol. % graphite were prepared by hot isostatic pressing, and their microstructure and coefficient of thermal expansion (CTE) were experimentally examined. The CTE decreased with increasing graphite volume fraction, from 17.8 × 10−6 K−1 for HIPed pure copper to 4.9 × 10−6 K−1 for 90 vol. % graphite. In the HIPed pure copper, the presence of cuprous oxide was detected by SEM-EDS. In contrast, Cu–graphite composites contained only a very small amount of oxygen (OHN analysis). There was only one exception, the composite with 90 vol. % graphite contained around 1.8 wt. % water absorbed inside the structure. The internal stresses in the composites were released during the first heating cycle of the CTE measurement. The permanent prolongation and shape of CTE curves were strongly affected by composition. After the release of internal stresses, the CTE curves of composites did not change any further. Finally, the modified Schapery model, including anisotropy and the clustering of graphite, was used to model the dependence of CTE on graphite volume fraction. Modeling suggested that the clustering of graphite via van der Waals bonds (out of hexagonal plane) is the most critical parameter and significantly affects the microstructure and CTE of the Cu–graphite composites when more than 30 vol. % graphite is present.

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“…Thus, the paired compressive and tensile stress were generated within the Gd 3 NbO 7 matrix and component phase GdNbO 4 , respectively. The XRD analysis, which could measure the stress of an arbitrary direction in a small area through the sin 2 ψ method, was used to measure the thermal residual stress [34,35]. The schematic diagram is shown in Fig.…”

Section: Residual Stress Tougheningmentioning

confidence: 99%

In-situ synthesis of gadolinium niobate quasi-binary composites with balanced mechanical and thermal properties for thermal barrier coatings

Han

Zong²,

Huang³

et al. 2022

J Adv Ceram

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Yttria-stabilized zirconia (YSZ) has been used as a thermal barrier coating (TBC) material in gas turbines for several decades. Although continuous efforts have been made to develop novel TBC materials that can work at a higher temperature, no single material other than YSZ has all the desired attributes for the TBCs. In this paper, we report the in-situ synthesis of quasi-binary GdNbO4/Gd3NbO7 composites based on the simple Gd2O3-Nb2O5 binary phase diagram. The fracture toughness of these quasi-binary composites is remarkably enhanced compared with the value predicted by the rule of mixtures because the ferroelastic domain switching is more activated due to the residual stress in the quasi-binary composites, which triggers more crack defections due to the enlarged process zone. Additionally, the Gd3NbO7 phase provides a low thermal conductivity due to the substantial chemical inhomogeneity, which diffuses phonons. Gd3NbO7/GdNbO4 exhibits a balanced thermal conductivity of 1.6 W/(m·K) at 1073 K and a toughness value of 2.76 MPa·m0.5, and these values are among the best comprehensive properties that have been obtained for new TBC materials. The work demonstrates a feasible approach of designing a new TBC material with balanced properties and can be easily fabricated.

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Nondestructive testing (NDT) techniques in the measurement of residual stresses in composite materials: An overview

Cited by 8 publications

References 163 publications

Theoretical Modeling for the Thermal Stability of Solid Targets in a Positron-Driven Muon Collider

Theoretical Modeling for the Thermal Stability of Solid Targets in a Positron-Driven Muon Collider

Structure and Thermal Expansion of Cu−90 vol. % Graphite Composites

In-situ synthesis of gadolinium niobate quasi-binary composites with balanced mechanical and thermal properties for thermal barrier coatings

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