Metal profiles with thermal barrier. Mechanical performance. Requirements, proof and tests for assessment

2015 ◽  
Keyword(s):  
Mechanical Performance ◽  
Thermal Barrier ◽  
Performance Requirements

scholarly journals Use of Treated Non-Ferrous Metallurgical Slags as Supplementary Cementitious Materials in Cementitious Mixtures

2021 ◽  
Vol 11 (9) ◽  
pp. 4028
Author(s):  
Asghar Gholizadeh Vayghan ◽  
Liesbeth Horckmans ◽  
Ruben Snellings ◽  
Arne Peys ◽  
Priscilla Teck ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Strength Development ◽  
Supplementary Cementitious Material ◽  
Performance Requirements ◽  
Metallurgical Slags ◽  
Leaching Behaviour ◽  
Kinetics Of

This research investigated the possibility of using metallurgical slags from the copper and lead industries as partial replacement for cement. The studied slags were fayalitic, having a mainly ferro-silicate composition with minor contents of Al2O3 and CaO. The slags were treated at 1200–1300 °C (to reduce the heavy metal content) and then granulated in water to promote the formation of reactive phases. A full hydration study was carried out to assess the kinetics of reactions, the phases formed during hydration, the reactivity of the slags and their strength activity as supplementary cementitious material (SCM). The batch-leaching behaviour of cementitious mixtures incorporating treated slags was also investigated. The results showed that all three slags have satisfactory leaching behaviour and similar performance in terms of reactivity and contribution to the strength development. All slags were found to have mediocre reactivity and contribution to strength, especially at early ages. Nonetheless, they passed the minimum mechanical performance requirements and were found to qualify for use in cement.

scholarly journals Experimental Study on Bi-Axial Mechanical Properties of Warp-knitted Meshes with and without Initial Notches

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1999 ◽  
Author(s):  
Huiqi Shao ◽  
Jianna Li ◽  
Nanliang Chen ◽  
Guangwei Shao ◽  
Jinhua Jiang ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Breaking Strength ◽  
Tensile Behavior ◽  
Mechanical Behaviors ◽  
Anisotropic Mesh ◽  
Structural Reinforcement ◽  
Performance Requirements ◽  
Axial Tensile ◽  
Notch Length ◽  
Notch Orientation

Warp-knitted meshes have been widely used for structural reinforcement of rigid, semi-rigid, and flexible composite materials. In order to meet the performance requirements of different engineering applications, four typical warp-knitted meshes (rectangular, square, circular, and diamond) were designed and developed. The mechanical behaviors of these meshes under mono-axial and multi-axial tensile loads were compared. The influence of the initial notch length and orientation on the mechanical performance was also analyzed. The results showed that the biaxial tensile behavior of warp-knitted meshes tended to be more isotropic. The anisotropy level of the diamond warp-knitted mesh was the lowest (λ = 0.099), while the rectangular one was the highest (λ = 0.502). The notch on a significantly anisotropic mesh was propagated along the direction of larger modulus, while for a not remarkably anisotropic mesh, notch propagation was probably consistent with the initial notch orientation. The breaking strength of warp-knitted meshes with the same initial notch orientation decreased with the increase in notch length in both the wale and course directions. For warp-knitted meshes with the same initial notch length, the breaking strength in the wale direction was kept stable at different notch orientations, while that in the course direction decreased remarkably with notch orientation from 0° to 90°.

On the use of high viscosity polymers in the fused filament fabrication process

2017 ◽  
Vol 23 (4) ◽  
pp. 727-735 ◽  
Author(s):  
Muhammad Hussam Khaliq ◽  
Rui Gomes ◽  
Célio Fernandes ◽  
João Nóbrega ◽  
Olga Sousa Carneiro ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
High Viscosity ◽  
Polymer Processing ◽  
General Purpose ◽  
Good Choice ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Performance Requirements ◽  
Functional Prototype ◽  
The One

Purpose This work aims to provide additional insights regarding the practicability of using conventional materials in the fused filament fabrication (FFF) process. Design/methodology/approach Two different acrylonitryle butadiene styrene (ABS) grades are studied and compared, aiming to check to what extent the regular ABS developed for conventional polymer processing, with a different rheology than the one provided for the FFF process, can also be used in this process (FFF). Findings The rheological results show that a general-purpose ABS (ABS-GP) melt is much more viscous and elastic than ABS-FFF. It is clear that using ABS-GP as feedstock material in the FFF process results in poor coalescence and adhesion between the extruded filaments, which has a detrimental effect on the mechanical properties of the printed specimens. Despite its lower performance, ABS-GP can be a good choice if the objective is to produce an aesthetical prototype. If the objective is to produce a functional prototype or a final part, its mechanical performance requirements will dictate the choice. Originality/value This work provides insightful information regarding the use of high viscosity materials on the 3D printing process.

scholarly journals Mechanisms Controlling the Performance and Durability of Thermal Barrier Coatings

2000 ◽  
Author(s):  
Daniel R. Mumm ◽  
Anthony G. Evans
Keyword(s):  
Thermal Cycling ◽  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Large Scale ◽  
Mechanical Performance ◽  
Thermal Protection ◽  
Crack Nucleation ◽  
Ceramic Coatings ◽  
Thermal Barrier ◽  
Barrier Coatings

Abstract Thermal protection systems based on ceramic thermal barrier coatings (TBCs) are used extensively to protect hot-section components in gas turbine engines. They comprise thermally insulating ceramic coatings, deposited on an aluminum-containing intermetallic bond coat (BC) that provides oxidation protection. A thin thermally-grown oxide (TGO layer forms between the TBC and BC during cyclic thermal exposure. Each of the system constituents evolves in service and all interact during thermal cycling to control the thermo-mechanical performance of the system. Exposed to thermal cycling conditions, TBC systems are susceptible to loss of adhesion and spalling failures. Multiple failure mechanisms exist, dependent upon differing thermal histoiy and processing approach for various coating systems. Coating failure is ultimately controlled by the large residual compression in the TGO and its role in amplifying the effects of imperfections in the vicinity of the TGO. The failure occurs through a process involving crack nucleation, propagation and coalescence events. For a particular commercial system, it is found that the TGO ‘ratchets’ into the bond coat with each thermal cycle, at an array of interfacial sites. The displacements induce strains in the superposed TBC that cause it to crack. The cracks extend laterally as the TGO ratcheting process proceeds, until the cracks from neighboring sites coalesce. Once this happens, the system fails by large scale buckling. It is shown that the displacements are ‘vectored’ by a lateral component of the growth strain in the TGO. The relative roles of bond coat visco-plasticity, initial interface morphology, and phase evolution are discuss. The behavior observed for this system is compared with predictions of a ratcheting model, as well as with the behavior observed for other commercial coating systems.

Studies on Magnetorheological Elastomers for Isolators

2013 ◽  
Vol 750-752 ◽  
pp. 1168-1171
Author(s):  
Xue Yang ◽  
Chang Geng Shuai ◽  
Shen Lin Yang
Keyword(s):  
Mechanical Performance ◽  
Magnetorheological Elastomers ◽  
Performance Requirements ◽  
New Type ◽  
Mr Effect

Magnetorheological (MR) elastomers are a new type of MR material. At present, most studies in this field are at laboratory stage, and practicability was rarely considered preparation of MR elastomer materials. Consequently, the existing materials with low overall properties cannot be applied in engineering. In this paper, the performance requirements for MR elastomers to be used in isolators were proposed. Then a type of practical MR elastomers for isolators was prepared, and its mechanical performance and MR effect were tested. The results show that the designed MR elastomers have high mechanical performance and high MR effect, and thus can be used in isolators.

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