Investigation of Impact Behavior of TIG Welded Inconel 718 at Aircraft Engine Operating Temperatures

2017 ◽  
Vol 890 ◽  
pp. 339-343
Author(s):  
Yagiz Uzunonat
Keyword(s):  
Inconel 718 ◽  
Impact Resistance ◽  
Aircraft Engine ◽  
Impact Behavior ◽  
Spectroscopy Analysis ◽  
Carbide Phases ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
The Impact ◽  
Pendulum Impact

In this work, Charpy notch pendulum impact test was performed on non-welded and TIG (Tungsten Inert Gas) welded Inconel 718 specimens at three different temperatures as 20°C, 500°C and 700°C. After the completion of tests, SEM (Scanning Electron Microscopy) inspection and EDX (Energy-Dispersive X-Ray Spectroscopy) analysis were performed for the microstructural examination of the specimens. Hardness measurements on the rupture zone of selected welded and non-welded specimens were also performed to make a better approach to interpretation of the impact behavior of material. Inspections indicated that hardness values in the heat affected zone of welded specimens dramatically decreased and they displayed higher ductility during fracture than non-welded samples due to partial softening of structure. The reason of further decrease in impact resistance of welded specimens was explained as the precipitation and coarsening of γ′′ and carbide phases in the interdendritic regions with increasing temperature.

Temperature Dependence of Hole Impact Ionization Coefficient in 4H-SiC Photodiodes

2009 ◽  
Vol 615-617 ◽  
pp. 311-314 ◽  
Author(s):  
W.S. Loh ◽  
J.P.R. David ◽  
B.K. Ng ◽  
Stanislav I. Soloviev ◽  
Peter M. Sandvik ◽  
...  
Keyword(s):  
Phonon Scattering ◽  
Impact Ionization ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Different Temperatures ◽  
Ionization Coefficients ◽  
Increasing Temperature ◽  
The Impact ◽  
Good Agreement ◽  
Ionization Rates

Hole initiated multiplication characteristics of 4H-SiC Separate Absorption and Multiplication Avalanche Photodiodes (SAM-APDs) with a n- multiplication layer of 2.7 µm were obtained using 325nm excitation at temperatures ranging from 300 to 450K. The breakdown voltages increased by 200mV/K over the investigated temperature range, which indicates a positive temperature coefficient. Local ionization coefficients, including the extracted temperature dependencies, were derived in the form of the Chynoweth expression and were used to predict the hole multiplication characteristics at different temperatures. Good agreement was obtained between the measured and the modeled multiplication using these ionization coefficients. The impact ionization coefficients decreased with increasing temperature, corresponding to an increase in breakdown voltage. This result agrees well with the multiplication characteristics and can be attributed to phonon scattering enhanced carrier cooling which has suppressed the ionization process at high temperatures. Hence, a much higher electric field is required to achieve the same ionization rates.

IMPACT RESISTANCE PROPERTIES OF KEVLAR/GLASS FIBER HYBRID COMPOSITE LAMINATES

2015 ◽  
Vol 76 (3) ◽  
Author(s):  
Norazean Shaari ◽  
Aidah Jumahat ◽  
M. Khafiz M. Razif
Keyword(s):  
Glass Fiber ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Impact Damage ◽  
Impact Resistance ◽  
Impact Behavior ◽  
Slight Reduction ◽  
Depth Of Penetration ◽  
Damage Degree ◽  
The Impact

In this paper, the impact behavior of Kevlar/glass fiber hybrid composite laminates was investigated by performing the drop weight impact test (ASTM D7136). Composite laminates were fabricated using vacuum bagging process with an epoxy matrix reinforced with twill Kevlar woven fiber and plain glass woven fiber. Four different types of composite laminates with different ratios of Kevlar to glass fiber (0:100, 20:80, 50:50 and 100:0) were manufactured. The effect of Kevlar/glass fiber content on the impact damage behavior was studied at 43J nominal impact energy. Results indicated that hybridization of Kevlar fiber to glass fiber improved the load carrying capability, energy absorbed and damage degree of composite laminates with a slight reduction in deflection. These results were further supported through the damage pattern analysis, depth of penetration and X-ray evaluation tests. Based on literature work, studies that have been done to investigate the impact behaviour of woven Kevlar/glass fiber hybrid composite laminates are very limited. Therefore, this research concentrates on the effect of Kevlar on the impact resistance properties of woven glass fibre reinforced polymer composites.

Impact Test for the Leading Edge of CMC Vane Based on Actual Aircraft Engine Field Data

2018 ◽  
Author(s):  
Kenro Obuchi ◽  
Fumiaki Watanabe ◽  
Hiroshi Kuroki ◽  
Hiroyuki Yagi ◽  
Kazuyoshi Arai
Keyword(s):  
Impact Test ◽  
Impact Resistance ◽  
Leading Edge ◽  
Aircraft Engine ◽  
Aircraft Engines ◽  
Turbine Vanes ◽  
Turbine Vane ◽  
Nickel Based Alloy ◽  
Weight Impact ◽  
The Impact

Ceramic matrix composites (CMCs) have lower density and a higher service temperature limit than nickel based alloys which have been used for turbine components of aircraft engines. These properties of CMCs have the potential to reduce the weight of turbine components and improve turbine thermal efficiency with a higher turbine inlet temperature (TIT). One of the technical issues of the CMC turbine vane is a relatively lower impact resistance than nickel based alloy turbine vanes. There are various previous works about impact resistance of CMCs, but there is little work that assumed actual engine conditions. The objective of this work was to verify the resistance of SiC/SiC CMC turbine vane to the impact phenomena that occur in the actual aircraft engine. The field damage survey was conducted on actual metal turbine vanes of commercial engines overhauled in IHI. The survey made it clear that the typical damage was less-than-0.127-mm-dent at the leading edge. In addition, the dropped weight impact test using the actual turbine airfoil which is made from a nickel based alloy was conducted at ambient temperature. The amount of energy required to make the dent of a certain size that was observed in actual metal turbine vanes was estimated. Then, the dropped weight impact test using the CMC test piece with a leading edge shape was conducted at the impact energy estimated by the metal turbine airfoil. The results showed that the failure mode of the CMC test piece was local damage with dents of a certain size and not a catastrophic failure mode. From this work, the damage to be assumed on CMC vane in actual aircraft engines was identified. As a future task, the effect of the damage to the fatigue capability of CMC turbine vanes needs to be investigated.

Experimental and Numerical Study of Basalt FRP Strip Strengthened RC Slabs under Impact Loads

2020 ◽  
Vol 20 (06) ◽  
pp. 2040001 ◽  
Author(s):  
Wensu Chen ◽  
Thong M. Pham ◽  
Mohamed Elchalakani ◽  
Huawei Li ◽  
Hong Hao ◽  
...  
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Numerical Study ◽  
Impact Resistance ◽  
Basalt Fiber ◽  
Impact Behavior ◽  
Impact Loads ◽  
Quantitative Measurements ◽  
Rc Slabs ◽  
The Impact

Basalt fiber-reinforced polymer (BFRP) has been applied for strengthening concrete structures. However, studies on reinforced concrete (RC) slabs strengthened by BFRP strips under impact loads are limited in open literature. This study investigates the efficiency of using BFRP strips with various strengthening layouts and anchoring schemes on the impact resistance of RC slabs. A total of 11 two-way square slabs were prepared and tested, including one reference specimen without strengthening and ten slabs strengthened with BFRP strips and/or anchors. The RC slabs were impacted by a drop weight with increasing height until slab failure. The observed failure modes include punching shear failure, BFRP sheet debonding and reinforcement fracture. The failure modes and the effects of using various strengthening schemes on the impact resistant capacity of RC slabs were examined. The quantitative measurements, such as impact velocity, indentation depth and diameter, were compared and discussed. In addition, numerical studies were carried out by using LS-DYNA to simulate the impact tests of RC slabs with and without BFRP strengthening. With the calibrated numerical model, the impact behavior of slabs with various dimensions and strengthening layouts under different impact intensities can be predicted with good accuracy.

scholarly journals Effect of Mold Temperature on the Impact Behavior and Morphology of Injection Molded Foams Based on Polypropylene Polyethylene–Octene Copolymer Blends

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 894 ◽  
Author(s):  
Santiago Muñoz-Pascual ◽  
Eduardo Lopez-Gonzalez ◽  
Cristina Saiz-Arroyo ◽  
Miguel Angel Rodriguez-Perez
Keyword(s):  
Impact Resistance ◽  
Mold Temperature ◽  
Impact Behavior ◽  
Critical Parameters ◽  
Crystalline Morphology ◽  
Copolymer Blends ◽  
Opposite Trend ◽  
Izod Impact ◽  
Injection Molded ◽  
The Impact

In this work, an isotactic polypropylene (PP) and a polyethylene–octene copolymer (POE) have been blended and injection-molded, obtaining solids and foamed samples with a relative density of 0.76. Different mold temperature and injection temperature were used. The Izod impact strength was measured. For solids, higher mold temperature increased the impact resistance, whereas in foams, the opposite trend was observed. In order to understand the reasons of this behavior, the morphology of the elastomeric phase, the crystalline morphology and the cellular structure have been studied. The presence of the elastomer near the skin in the case of high mold temperature can explain the improvement produced with a high mold temperature in solids. For foams, aspects as the elastomer coarsening in the core of the sample or the presence of a thicker solid skin are the critical parameters that justify the improved behavior of the materials produced with a lower mold temperature.

scholarly journals Effect of Three-dimensional Printing with Nanotubes on Impact Resistance

2019 ◽  
Author(s):  
Anne Schmitz
Keyword(s):  
Mechanical Properties ◽  
Lower Limb ◽  
Impact Resistance ◽  
Three Dimensional ◽  
Three Dimensional Printing ◽  
Impact Tester ◽  
The Impact ◽  
Dimensional Printing ◽  
Pendulum Impact ◽  
Pendulum Impact Tester

Abstract The types of biomedical devices that can be three-dimensional printed (3DP) is limited by the mechanical properties of the resulting materials. As a result, much research has focused on adding carbon nanotubes (CNT) to these photocurable polymers to make them stronger. However, there is little to no data on how CNTs affect the impact resistance of these polymers, an important property when designing and manufacturing lower limb prosthetics. The objective of this study was to expand the use of 3DP to prosthetics by testing the hypothesis that adding CNTs to a stereolithographic (SLA) photocurable resin will result in a cured polymer with increased impact resistance. Twenty-six total specimens: 13 with nanotubes and 13 without nanotubes, were printed on a Form2 SLA printer. Once all the specimens were printed, washed, and cured, the impact resistance was quantified using a pendulum impact tester in a notched Izod configuration. Contrary to the hypothesis, the specimens with SWCNTs (0.312 ± 0.036 ft*lb/in) had a significantly lower impact resistance compared to the non-SWCNT specimens (0.364 ± 0.055 ft*lb/in), U = 34.0, p = 0.004. This decreased impact resistance may be due to voids in the printed polymer around the aggregated nanotubes. Thus, SLA polymers still do not have the impact strength needed to be used for a full lower limb prosthetic.

Can ultrasonic parameters affect the impact and water barrier properties of nano-clay filled glass fiber/polyester composites?

2020 ◽  
pp. 152808372096073
Author(s):  
AA Megahed ◽  
MA Agwa ◽  
M Megahed
Keyword(s):  
Glass Fiber ◽  
Impact Resistance ◽  
Impact Behavior ◽  
Water Barrier ◽  
Nano Clay ◽  
Polyester Matrix ◽  
Ultrasonic Parameters ◽  
Polyester Composites ◽  
Sonication Parameters ◽  
The Impact

Good dispersion of the nanoparticles into the polymer is considered a critical issue, as it can provide higher strength and stiffness while poor dispersion is seen to decrease those properties. In the present work, the effect of three ultrasonic parameters (amplitude, time and cycle of sonication) on sonication technique for dispersing 1 wt.% nano-clay in polyester matrix was investigated. To disperse the nano-clay into the polyester matrix, sonication frequencies of 40% and 80%, sonication times of 0.5, 1 and 2 hours and pulse of 0.5 and 1 cycle were used. The effect of these ultrasonication parameters on water barrier and impact behavior of unfilled and filled glass fiber (GF)/polyester with nano-clay under dry, distilled and seawater conditions was studied. Results showed that, water absorption of nano-filled composites dispersed with all sonication parameters is lower than that of unfilled glass fiber/polyester composites immersed in distilled and seawater. Nano-clay filled GF/polyester composites showed an improvement in impact resistance under dry, distilled and seawater conditions with all sonication parameters. Among the used sonication parameters; time of 2 hours, amplitude of 40% and 0.5 cycle was found as the best parameter which resulted in the maximum enhancement in impact resistance, due to the addition of nano-clay to GF/polyester, of 8.2%, 14% and 19.6% under dry, distilled water and seawater conditions, respectively. Nonlinear minimization approach was exploited using MAPLE commercial software in order to find the suitable fit to the models of Fick and Langmuir. Diffusion coefficients for different sonication times were computed.

Preparation of auxetic warp-knitted spacer fabric impregnated with shear thickening fluid for low-velocity impact resistance

2020 ◽  
pp. 152808372092701 ◽  
Author(s):  
Wanli Xu ◽  
Biao Yan ◽  
Dongmei Hu ◽  
Pibo Ma
Keyword(s):  
Shear Rate ◽  
Energy Absorption ◽  
Impact Resistance ◽  
Shear Thickening ◽  
Weight Fraction ◽  
Low Velocity Impact ◽  
Impact Behavior ◽  
Shear Thickening Fluid ◽  
Spacer Fabric ◽  
The Impact

This paper reports the preparation of auxetic warp-knitted spacer fabric impregnated with shear thickening fluid and studied its impact behavior under low-velocity impact loading. The shear thickening fluids have been prepared by mechanically dispersing 12 nm silica particles with weight fraction of 10, 15, 20, and 25% in various carriers (PEG200, PEG400, and PEG600). Rheological results indicate that shear thickening fluid experiences shear thickening transition at a specific shear rate. The critical shear rate reduces, and initial viscosity and maximum viscosity increase with the increase of silica weight fraction. The higher molecular weight of polyethylene glycols can lead to lower critical shear rate. The impact process of composite under impact loading can be divided into three stages. The warp-knitted spacer fabric with different negative Poisson’s ratio has a significant effect on the impact behavior. The warp-knitted spacer fabric with better auxetic performance endows composite better impact resistance, the specific performance is the deformation depth, and energy absorption and peak load increase with the increase of auxetic effect of fabric. The silica weight fraction of shear thickening fluid can increase the energy absorption of composite due to the shear thickening transition of shear thickening fluid. Shear thickening fluid has a synergistic effect with the auxetic warp-knitted spacer fabric on impact resistance of composite. The various carriers have no obvious influence on the overall energy absorption and impact load of composites.

EFFECT OF ANTIBIOTICS AUGMENTATION AND STORAGE CONDITION ON IMPACT RESISTANCE OF ORTHOPEDIC BONE CEMENT

2017 ◽  
Vol 17 (01) ◽  
pp. 1750019
Author(s):  
MARYAM KALANTARI ◽  
ATA HASHEMI
Keyword(s):  
Impact Strength ◽  
Bone Cement ◽  
Storage Temperature ◽  
Impact Resistance ◽  
Storage Condition ◽  
Four Point Bending ◽  
Pmma Bone Cement ◽  
Different Temperatures ◽  
Aging Conditions ◽  
The Impact

Antibiotic-impregnated poly(methyl methacrylate) (PMMA) bone cement has been successfully used to treat infected joint arthroplasties and surgeons have advocated the use of antibiotic-treated bone cement to prevent possible infections in joint replacement surgeries. However, there is a concern that this addition may adversely affect the mechanical properties of the bone cement. In most cases, the addition of antibiotics to bone cement has been reported to lower its mechanical strength. The uniaxial, biaxial and three/four point bending tests of antibiotic-impregnated bone cement have been extensively performed and well documented. However, only a few documents have focused on the impact strength of bone cement. The present study reports the impact tests of control and antibiotic loaded bone cements at different temperatures and aging conditions. According to the results, the addition of gentamicin or vancomycin significantly reduced the samples' impact strength. Moreover, the samples aged in saline at 23[Formula: see text]C were more resistant than the samples aged in air at 23[Formula: see text]C. Furthermore, raising the storage temperature from 23[Formula: see text]C to 37[Formula: see text]C significantly lowered the bone cement's impact strength in both control and antibiotic loaded samples.

scholarly journals Spectroscopic and Molecular Modeling Investigation on the Interaction between Folic Acid and Bovine Lactoferrin from Encapsulation Perspectives

Foods ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 744
Author(s):  
Iuliana Aprodu ◽  
Loredana Dumitrașcu ◽  
Gabriela Râpeanu ◽  
Gabriela-Elena Bahrim ◽  
Nicoleta Stănciuc
Keyword(s):  
Folic Acid ◽  
Molecular Modeling ◽  
Thermal Treatment ◽  
Tertiary Structure ◽  
Emission Spectra ◽  
Bovine Lactoferrin ◽  
Different Temperatures ◽  
Static Mechanism ◽  
Increasing Temperature ◽  
The Impact

The impact of thermal treatment on the ability of lactoferrin (FL) to bind folic acid (FA) was investigated by employing fluorescence spectroscopy, molecular dynamics and docking tests. The structural and conformational particularities of LF upon heating at 80 °C and 100 °C were first estimated based on the intrinsic fluorescence changes in respect to the native protein. The emission spectra indicated gradual unfolding events accompanied by Trp exposure with increasing temperature. In agreement with the experimental results, molecular modeling investigations showed that the secondary and tertiary structure of LF are slightly affected by the thermal treatment. Some minor unfolding events related particularly to the α-helical regions of LF were observed when the temperature increased to 100 °C. The LF fluorescence quenching upon FA addition indicated that a static mechanism stands behind LF-FA complex formation. Regardless of the simulated temperature, the hydrogen bonds played an important role in regulating the interaction between the protein and ligand. FA binding to LF equilibrated at different temperatures occurred spontaneously, and all complexes displayed good thermodynamic stability. The obtained results support the suitability of LF as biocompatible material, for obtaining micro- and nanoparticles for delivery of dietary supplements or for enhancing the functionality of target delivery systems.

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