scholarly journals EFFECTS OF ARAMID SEWING YARN TYPE AND FABRIC COMPOSITIONS ON SOME SEAM PROPERTIES OF HIGH PERFORMANCE FIRE RETARDANT FABRICS

2021 ◽  
Vol 2021 ◽  
pp. 116-122
Author(s):  
S. Kara
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Mechanical Performance ◽  
Fire Retardant ◽  
Occupational Hazards ◽  
Fire Retardancy ◽  
Preliminary Work ◽  
End Use ◽  
Reference Samples ◽  
Textile Article

High performance fire retardant textiles are utilized in different end-use areas such as workwear, firefighter garments, military textiles etc. These textiles are produced to protect the wearer against harsh environmental/occupational hazards and to bear forces during occupation. In the literature, fire-retardancy and mechanical performance of high performance fire retardant textiles are searched in details. Nevertheless, in most of these studies, samples were in the form of fibres or fabrics. When the fabrics are cut and sewn together to form a textile article, their mechanical properties change along the seam lines. In spite of this fact, seam properties of high performance fire retardant fabrics were not studied in the literature, systematically. Therefore, in this study, some seam properties of high performance fire retardant fabrics were studied as a preliminary work in this subject. According to results, seam strength of all samples were considerably lower when compared to strength of non-sewn reference samples. Strength differences were detected between the samples sewn with meta–aramid sewing yarn and para-aramid sewing yarn. Seam elongation and seam slippage values were similar for both sewing yarn types.

scholarly journals Characterisation of a High-Performance Al–Zn–Mg–Cu Alloy Designed for Wire Arc Additive Manufacturing

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1610 ◽  
Author(s):  
Paulo J. Morais ◽  
Bianca Gomes ◽  
Pedro Santos ◽  
Manuel Gomes ◽  
Rudolf Gradinger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Additive Manufacturing ◽  
High Performance ◽  
Mechanical Performance ◽  
Fluorescence Analysis ◽  
Cold Metal Transfer ◽  
Direction Parallel ◽  
X Ray ◽  
Wire Arc Additive Manufacturing

Ever-increasing demands of industrial manufacturing regarding mechanical properties require the development of novel alloys designed towards the respective manufacturing process. Here, we consider wire arc additive manufacturing. To this end, Al alloys with additions of Zn, Mg and Cu have been designed considering the requirements of good mechanical properties and limited hot cracking susceptibility. The samples were produced using the cold metal transfer pulse advanced (CMT-PADV) technique, known for its ability to produce lower porosity parts with smaller grain size. After material simulations to determine the optimal heat treatment, the samples were solution heat treated, quenched and aged to enhance their mechanical performance. Chemical analysis, mechanical properties and microstructure evolution were evaluated using optical light microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray fluorescence analysis and X-ray radiography, as well as tensile, fatigue and hardness tests. The objective of this research was to evaluate in detail the mechanical properties and microstructure of the newly designed high-performance Al–Zn-based alloy before and after ageing heat treatment. The only defects found in the parts built under optimised conditions were small dispersed porosities, without any visible cracks or lack of fusion. Furthermore, the mechanical properties are superior to those of commercial 7xxx alloys and remarkably independent of the testing direction (parallel or perpendicular to the deposit beads). The presented analyses are very promising regarding additive manufacturing of high-strength aluminium alloys.

scholarly journals Structure, Mechanical Performance, and Dimensional Stability of Radiata Pine (Pinus radiata D. Don) Scrimbers

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Jinguang Wei ◽  
Fei Rao ◽  
Yuxiang Huang ◽  
Yahui Zhang ◽  
Yue Qi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Pinus Radiata ◽  
Dimensional Stability ◽  
High Performance ◽  
Water Resistance ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Radiata Pine ◽  
Specific Strength ◽  
Shearing Strength

Natural wood has certain advantages such as good processability and high specific strength and thus has been used for millennium as a structural material. But the mechanical performance and water resistance, particularly for fast-growing species, are unsatisfactory for high-end applications. In this study, the “new-type” scrimber technology was introduced to radiata pine (Pinus radiata D. Don) scrimbers. The structure, mechanical properties, and dimensional stability of the scrimber panels were investigated. Results showed that OWFMs as basic units of scrimber had been very even in size and superior permeability. The scrimbers exhibited a three-dimensional porous structure, and the porosity had a decrease with increasing density. Both OWFMs and densification contributed to the high performance in terms of mechanical properties and water resistance. The flexural, compressive, and short-beam shearing strength were significantly enhanced with increasing density. As the density was 0.80 g cm−3, the flexural strength (MOR) was approximately 120 MPa, much larger than many selected wood-based panels. Moreover, the water resistance and dimensional stability also were closely related to the density. At the density of 1.39 g cm−3, the water absorption rate and thinness swelling rate of the panels in boiled water were only 19% and 5.7%, respectively.

Effect of Zr Diffusion Barrier Properties on the Irradiation Performance of U-10Mo Monolithic Fuel Plate

2019 ◽  
Author(s):  
Walid Mohamed ◽  
Hakan Ozaltun ◽  
Hee Seok Roh
Keyword(s):  
Mechanical Properties ◽  
Diffusion Barrier ◽  
High Performance ◽  
Mechanical Performance ◽  
Plate Thickness ◽  
Barrier Properties ◽  
Element Analysis ◽  
Uranium Fuel ◽  
High Enrichment ◽  
Irradiation Performance

Abstract The most recent design of U-Mo monolithic fuel as adopted by the U.S. for the conversion of its High Performance Research Reactors (USHPRR) from high enrichment uranium (HEU) to low enrichment uranium fuel (LEU, < 20% U235) consists of a high density (LEU) U-10Mo fuel sandwiched between Zirconium (Zr) diffusion barriers and encapsulated in aluminum (AA6061) cladding. In this work, finite element analysis (FEA) was used to evaluate effect of Zr diffusion barrier properties on the thermal and mechanical performance of a U-10Mo monolithic fuel plate by considering possible variation in thermal and mechanical properties of the Zr diffusion barrier. Possible variation in thermo-mechanical properties of the Zr diffusion barrier were determined and a simulation matrix was designed accordingly. Analyses of simulation results included determination of global peak stresses in the fuel, Zr diffusion barrier, and cladding sections as well as the plate thickness profile at a transverse section toward the top side of the plate. Results showed that variation in yield stress, elastic modulus and thermal conductivity of the Zr diffusion barrier has negligible effect on the thermal and mechanical performance of the monolithic fuel plate. The effect of variation in these properties was found to be limited to the barrier section itself, which may be attributed to the relatively smaller thickness of that section compared to the fuel and cladding sections of the fuel plate.

scholarly journals Quantifying High-Performance Material Microstructure Using Nanomechanical Tools with Visual and Frequency Analysis

Scanning ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Emil Sandoz-Rosado ◽  
Michael R. Roenbeck ◽  
Kenneth E. Strawhecker
Keyword(s):  
Mechanical Properties ◽  
Frequency Analysis ◽  
Visual Processing ◽  
High Performance ◽  
Mechanical Performance ◽  
Structure Property ◽  
Spatially Resolved ◽  
Macro Scale ◽  
Organization Strategy ◽  
Stiffness Scanning

High-performance materials like ballistic fibers have remarkable mechanical properties owing to specific patterns of organization ranging from the molecular scale, to the micro scale and macro scale. Understanding these strategies for material organization is critical to improving the mechanical properties of these high-performance materials. In this work, atomic force microscopy (AFM) was used to detect changes in material composition at an extremely high resolution with transverse-stiffness scanning. New methods for direct quantification of material morphology were developed, and applied as an example to these AFM scans, although these methods can be applied to any spatially-resolved scans. These techniques were used to delineate between subtle morphological differences in commercial ultra-high-molecular-weight polyethylene (UHMWPE) fibers that have different processing conditions and mechanical properties as well as quantify morphology in commercial Kevlar®, a high-performance material with an entirely different organization strategy. Both frequency analysis and visual processing methods were used to systematically quantify the microstructure of the fiber samples in this study. These techniques are the first step in establishing structure-property relationships that can be used to inform synthesis and processing techniques to achieve desired morphologies, and thus superior mechanical performance.

Influence of Sintering Parameters on the Mechanical Performance of PM Steels Pre-Alloyed with Chromium

2007 ◽  
Vol 534-536 ◽  
pp. 545-548 ◽  
Author(s):  
Ola Bergman ◽  
Björn Lindqvist ◽  
Sven Bengtsson
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
High Performance ◽  
Mechanical Performance ◽  
Sintering Temperature ◽  
Oxide Reduction ◽  
Low Oxygen ◽  
Positive Effects ◽  
Partial Pressures

Powder grades pre-alloyed with 1.5-3 wt% chromium are suitable for PM steel components in high performance applications. These materials can be successfully sintered at the conventional temperature 1120 °C, although well-monitored sintering atmospheres with low oxygen partial pressures (<10-17-10-18 atm) are required to avoid oxidation. Mechanical properties of the Cralloyed PM grades are enhanced by a higher sintering temperature in the range 1120-1250 °C, due to positive effects from pore rounding, increased density and more effective oxide reduction. A material consisting of Astaloy CrM, which is pre-alloyed with 3 wt% Cr and 0.5 wt% Mo, and 0.6 wt% graphite obtains an ultimate tensile strength of 1470 MPa combined with an impact strength of 31 J at density 7.1 g/cm3, after sintering at 1250 °C followed by cooling at 2.5 °C/s and tempering.

Parametric study on tensile and flexural properties of ULTEM 1010 specimens fabricated via FDM

2021 ◽  
Vol 27 (2) ◽  
pp. 429-451
Author(s):  
Chrysoula Pandelidi ◽  
Tobias Maconachie ◽  
Stuart Bateman ◽  
Ingomar Kelbassa ◽  
Sebastian Piegert ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Process Parameters ◽  
Computer Aided Design ◽  
High Performance ◽  
Mechanical Performance ◽  
Fused Deposition Modelling ◽  
Controlled Cooling ◽  
Content Type ◽  
Fused Deposition

Purpose Fused deposition modelling (FDM) is increasingly being explored as a commercial fabrication method due to its ability to produce net or near-net shape parts directly from a computer-aided design model. Other benefits of technology compared to conventional manufacturing include lower cost for short runs, reduced product lead times and rapid product design. High-performance polymers such as polyetherimide, have the potential for FDM fabrication and their high-temperature capabilities provide the potential of expanding the applications of FDM parts in automotive and aerospace industries. However, their relatively high glass transition temperature (215 °C) causes challenges during manufacturing due to the requirement of high-temperature build chambers and controlled cooling rates. The purpose of this study is to investigate the mechanical properties of ULTEM 1010, an unfilled polyetherimide grade. Design/methodology/approach In this research, mechanical properties were evaluated through tensile and flexural tests. Analysis of variance was used to determine the significance of process parameters to the mechanical properties of the specimens, their main effects and interactions. The fractured surfaces were analysed by scanning electron microscopy and optical microscopy and porosity was assessed by X-ray microcomputed tomography. Findings A range of mean tensile and flexural strengths, 60–94 MPa and 62–151 MPa, respectively, were obtained highlighting the dependence of performance on process parameters and their interactions. The specimens were found to fracture in a brittle manner. The porosity of tensile samples was measured between 0.18% and 1.09% and that of flexural samples between 0.14% and 1.24% depending on the process parameters. The percentage porosity was found to not directly correlate with mechanical performance, rather the location of those pores in the sample. Originality/value This analysis quantifies the significance of the effect of each of the examined process parameters has on the mechanical performance of FDM-fabricated specimens. Further, it provides a better understanding of the effect process parameters and their interactions have on the mechanical properties and porosity of FDM-fabricated polyetherimide specimens. Additionally, the fracture surface of the tested specimens is qualitatively assessed.

Intumescent PP Blends

2003 ◽  
Vol 11 (8) ◽  
pp. 691-702 ◽  
Author(s):  
X. Almeras ◽  
M. Le Bras ◽  
S. Bourbigot ◽  
P. Hornsby ◽  
G. Marosi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flame Retardancy ◽  
Fire Retardant ◽  
Polyamide 6 ◽  
Ammonium Polyphosphate ◽  
Fire Performance ◽  
Fire Retardancy ◽  
Pp Blends

One way to improve the fire performance of polymers is by the development of intumescent systems. The addition of ammonium polyphosphate/polyamide-6 is known to provide flame retardancy in many polymers via an intumescent process. The development of appropriate formulations is limited by their mechanical properties. This study shows that polypropylene based intumescent blends are efficient fire retardant systems and that acceptable mechanical properties can be obtained. It is also shown that adding talc improves the mechanical properties of intumescent polypropylene formulations without decreasing their fire retardancy.

scholarly journals Bone-inspired microarchitectures achieve enhanced fatigue life

2019 ◽  
Vol 116 (49) ◽  
pp. 24457-24462 ◽  
Author(s):  
Ashley M. Torres ◽  
Adwait A. Trikanad ◽  
Cameron A. Aubin ◽  
Floor M. Lambers ◽  
Marysol Luna ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Cancellous Bone ◽  
High Performance ◽  
Mechanical Performance ◽  
Lattice Structures ◽  
Structural Elements ◽  
Naturally Occurring ◽  
Superior Mechanical Properties ◽  
The Cost

Microarchitectured materials achieve superior mechanical properties through geometry rather than composition. Although ultralightweight microarchitectured materials can have high stiffness and strength, application to durable devices will require sufficient service life under cyclic loading. Naturally occurring materials provide useful models for high-performance materials. Here, we show that in cancellous bone, a naturally occurring lightweight microarchitectured material, resistance to fatigue failure is sensitive to a microarchitectural trait that has negligible effects on stiffness and strength—the proportion of material oriented transverse to applied loads. Using models generated with additive manufacturing, we show that small increases in the thickness of elements oriented transverse to loading can increase fatigue life by 10 to 100 times, far exceeding what is expected from the associated change in density. Transversely oriented struts enhance resistance to fatigue by acting as sacrificial elements. We show that this mechanism is also present in synthetic microlattice structures, where fatigue life can be altered by 5 to 9 times with only negligible changes in density and stiffness. The effects of microstructure on fatigue life in cancellous bone and lattice structures are described empirically by normalizing stress in traditional stress vs. life (S-N) curves by √ψ, where ψ is the proportion of material oriented transverse to load. The mechanical performance of cancellous bone and microarchitectured materials is enhanced by aligning structural elements with expected loading; our findings demonstrate that this strategy comes at the cost of reduced fatigue life, with consequences to the use of microarchitectured materials in durable devices and to human health in the context of osteoporosis.

Performance of Foldcores Mechanical Properties and Testing

2013 ◽  
Author(s):  
Marc Grzeschik
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Mechanical Performance ◽  
Aircraft Design ◽  
International Standards ◽  
Mathematical Methods ◽  
Lightweight Structures ◽  
Base Materials ◽  
Aramid Fibres ◽  
Glass Carbon

Foldcores are folded open cellular structures which are currently under development at Institute of Aircraft Design (IFB). The IFB has generated an integrated manufacturing process to produce foldcores, starting with the mathematical methods to design the required foldcore geometry to the point of realizing them in an automated and continuous fashion. By isometric folding of planar base materials foldcores can and have already been manufactured out of a large variety of materials: cardboard, papers, metals (aluminum, steel, titanium), different thermoplastic films (PC, PVC, PPSU, PEEK) as well as advanced fibre reinforced materials (glass, carbon, aramid fibres). For the technical use of foldcores in sandwich structures it is necessary to supply a competitive level of mechanical performance. We discuss the mechanical properties of foldcores compared to other state of the art core materials. We detail the testing methods used to determine compression and shear strengths and stiffnesses, which are based upon international standards. Evaluation of the test results show potential for the use of foldcores in high performance lightweight structures, especially considering their unique multifunctional applicability.

scholarly journals The Effect of Annealing on Additive Manufactured ULTEM™ 9085 Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2907
Author(s):  
Yongjie Zhang ◽  
Seung Ki Moon
Keyword(s):  
Mechanical Properties ◽  
Thermal Annealing ◽  
Thermal Stresses ◽  
Mechanical Performance ◽  
Annealing Process ◽  
Aviation Industry ◽  
Fused Filament Fabrication ◽  
Jigs And Fixtures ◽  
Thermal Annealing Process ◽  
End Use

Fused filament fabrication (FFF) is increasingly adopted for direct manufacturing of end use parts in an aviation industry. However, the application of FFF technique is still restricted to manufacturing low criticality lightly loaded parts, due to poor mechanical performance. To alleviate the mechanical performance issue, thermal annealing process is frequently utilized. However, problems such as distortion issues and the need for jigs and fixtures limit the effectiveness of the thermal annealing process, especially for low volume complex FFF parts. In this research, a novel low temperature thermal annealing is proposed to address the limitations in conventional annealing. A modified orthogonal array design is applied to investigate the performance of ULTEM™ 9085 FFF coupons. Further, the coupons are annealed with specialized support structures, which are co-printed with the coupons during the manufacturing process. Once the annealing process is completed, multiscale characterizations are performed to identify the mechanical properties of the specimens. Geometrical measurement of post annealed specimens indicates an expansion in the layering direction, which indicates relief of thermal stresses. Moreover, annealed coupons show an improvement in tensile strength and reduction in strain concentration. Mesostructure and fracture surface analysis indicate an increase in ductility and enhanced coalescence. This research shows that the proposed annealing methodology can be applied to enhance the mechanical performance of FFF parts without significant distortion.

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