Impact Design Methods for Ceramic Components in Gas Turbine Engines

1993 ◽  
Vol 115 (1) ◽  
pp. 83-90 ◽  
Author(s):  
J. Song ◽  
J. Cuccio ◽  
H. Kington
Keyword(s):  
Impact Damage ◽  
Impact Resistance ◽  
Local Stress ◽  
Taguchi Methods ◽  
Design Parameters ◽  
Material Strength ◽  
Stress And Strain ◽  
Ongoing Research ◽  
Local Impact ◽  
The Impact

Garrett Auxiliary Power Division of Allied-Signal Aerospace Company is developing methods to design ceramic turbine components with improved impact resistance. In an ongoing research effort under the DOE/NASA-funded Advanced Turbine Technology Applications Project (ATTAP), two different modes of impact damage have been identified and characterized: local damage and structural damage. Local impact damage to Si3N4 impacted by spherical projectiles usually takes the form of ring and/or radial cracks in the vicinity of the impact point. Baseline data from Si3N4 test bars impacted by 1.588-mm (0.0625-in.) diameter NC-132 projectiles indicates the critical velocity at which the probability of detecting surface cracks is 50 percent equalled 130 m/s (426 ft/sec). A microphysics-based model that assumes damage to be in the form of microcracks has been developed to predict local impact damage. Local stress and strain determine microcrack nucleation and propagation, which in turn alter local stress and strain through modulus degradation. Material damage is quantified by a “damage parameter” related to the volume fraction of microcracks. The entire computation has been incorporated into the EPIC computer code. Model capability is being demonstrated by simulating instrumented plate impact and particle impact tests. Structural impact damage usually occurs in the form of fast fracture caused by bending stresses that exceed the material strength. The EPIC code has been successfully used to predict radial and axial blade failures from impacts by various size particles. This method is also being used in conjunction with Taguchi experimental methods to investigate the effects of design parameters on turbine blade impact resistance. It has been shown that significant improvement in impact resistance can be achieved by using the configuration recommended by Taguchi methods.

scholarly journals Impact Design Methods for Ceramic Components in Gas Turbine Engines

1991 ◽  
Author(s):  
J. Song ◽  
J. Cuccio ◽  
H. Kington
Keyword(s):  
Impact Damage ◽  
Impact Resistance ◽  
Local Stress ◽  
Taguchi Methods ◽  
Design Parameters ◽  
Material Strength ◽  
Stress And Strain ◽  
Ongoing Research ◽  
Local Impact ◽  
The Impact

Garrett Auxiliary Power Division of Allied-Signal Aerospace Company is developing methods to design ceramic turbine components with improved impact resistance. In an ongoing research effort under the DOE/NASA-funded Advanced Turbine Technology Applications Project (ATTAP), two different modes of impact damage have been identified and characterized: Local damage and structural damage. Local impact damage to Si3N4 impacted by spherical projectiles usually takes the form of ring and/or radial cracks in the vicinity of the impact point. Baseline data from Si3N4 test bars impacted by 1.588 mm (0.0625 inch) diameter NC-132 projectiles indicates the critical velocity at which the probability of detecting surface cracks is 50 percent equalled 130 m/sec (426 ft/sec). A microphysics-based model that assumes damage to be in the form of microcracks has been developed to predict local impact damage. Local stress and strain determine microcrack nucleation and propagation, which in turn alter local stress and strain through modulus degradation. Material damage is quantified by a “damage parameter” related to the volume fraction of microcracks. The entire computation has been incorporated into the EPIC computer code. Model capability is being demonstrated by simulating instrumented plate impact and particle impact tests. Structural impact damage usually occurs in the form of fast fracture caused by bending stresses that exceed the material strength. The EPIC code has been successfully used to predict radial and axial blade failures from impacts by various size particles. This method is also being used in conjunction with Taguchi experimental methods to investigate the effects of design parameters on turbine blade impact resistance. It has been shown that significant improvement in impact resistance can be achieved by using the configuration recommended by the Taguchi methods.

scholarly journals Sandwich panel with in-plane honeycombs in different Poisson's ratio under low to medium impact loads

2021 ◽  
Vol 60 (1) ◽  
pp. 145-157
Author(s):  
Yi Luo ◽  
Ke Yuan ◽  
Lumin Shen ◽  
Jiefu Liu
Keyword(s):  
Poisson’S Ratio ◽  
Sandwich Panel ◽  
Impact Force ◽  
Impact Resistance ◽  
Poisson's Ratio ◽  
Compression Performance ◽  
Post Impact ◽  
Local Impact ◽  
Collapse Behavior ◽  
The Impact

Abstract In this study, a series of in-plane hexagonal honeycombs with different Poisson's ratio induced by topological diversity are studied, considering re-entrant, semi-re-entrant and convex cells, respectively. The crushing strength of honeycomb in terms of Poisson's ratio is firstly presented. In the previous research, we have studied the compression performance of honeycomb with different negative Poisson's ratio. In this study, a comparative study on the local impact resistance of different sandwich panels is conducted by considering a spherical projectile with low to medium impact speed. Some critical criteria (i.e. local indentation profile, global deflection, impact force and energy absorption) are adopted to analyze the impact resistance. Finally, an influential mechanism of Poisson's ratio on the local impact resistance of sandwich panel is studied by considering the variation of core strength and post-impact collapse behavior.

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.

scholarly journals Influence of Orthotropy on Biomechanics of Peri-Implant Bone in Complete Mandible Model with Full Dentition

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Xi Ding ◽  
Sheng-Hui Liao ◽  
Xing-Hao Zhu ◽  
Hui-Ming Wang
Keyword(s):  
Orthotropic Material ◽  
Tooth Enamel ◽  
Local Stress ◽  
Isotropic Case ◽  
Stress And Strain ◽  
Isotropic Model ◽  
Bone Interface ◽  
Multiple Data ◽  
Cad Models ◽  
The Impact

Objective.The study was to investigate the impact of orthotropic material on the biomechanics of dental implant, based on a detailed mandible with high geometric and mechanical similarity.Materials and Methods.Multiple data sources were used to elaborate detailed biological structures and implant CAD models. In addition, an extended orthotropic material assignment methodology based on harmonic fields was used to handle the alveolar ridge region to generate compatible orthotropic fields. The influence of orthotropic material was compared with the commonly used isotropic model and simplified orthotropic model.Results.The simulation results showed that the values of stress and strain on the implant-bone interface almost increased in the orthotropic model compared to the isotropic case, especially for the cancellous bone. However, the local stress concentration was more obvious in the isotropic case compared to that in orthotropic case. The simple orthotropic model revealed irregular stress and strain distribution, compared to the isotropic model and the real orthotropic model. The influence of orthotropy was little on the implant, periodontal ligament, tooth enamel, and dentin.Conclusion.The orthotropic material has significant effect on stress and strain of implant-bone interface in the mandible, compared with the isotropic simulation. Real orthotropic mechanical properties of mandible should be emphasized in biomechanical studies of dental implants.

Containment and Arrest of Blade Shedding in Gas Turbine Engines Using Novel Dual-Ring Design

2021 ◽  
Author(s):  
Prayers Roy ◽  
Shaker A. Meguid
Keyword(s):  
Energy Absorption ◽  
Impact Damage ◽  
Impact Resistance ◽  
High Energy ◽  
Element Analysis ◽  
Single Ring ◽  
High Energy Absorption ◽  
Interfacial Gap ◽  
The Impact ◽  
Dual Ring

Abstract In this paper, we examine the energy absorption and containment capabilities of a newly proposed dual-ring design accounting for interactions between a released blade and fully bladed fan disk using 3D finite element analysis. The components of this dual-ring design are strategically selected to ensure high energy absorption and high impact resistance, thus leading to reduced damage of the disk and increased safety. Three containment ring designs are examined: (i) conventional single-ring design composed of one of titanium, aluminum or Kevlar, (ii) a newly proposed aluminium-Kevlar dual-ring arrangement, and (iii) dual-ring arrangement with an interfacial gap between them to arrest and contain the released blade and ensure free passage of the trailing blades. The results of our numerical simulations indicate that although the single-ring design resists penetration and contains the released blade within the confines of the disk, it does not remove the released blade from the path of the trailing blades leading to severe damage to the fan disk. On the contrary, our new dual-ring design, which contains an interfacial gap, has potential to successfully arrest the released blade within the confines of the ring and out of the path of the trailing blades. This design significantly can reduce the impact damage to the fan disk and reduces kinetic energy of the released blade to near zero in less than half a rotation of the fan disk.

Impact Resistance of SM Joints Formed With ICA

2002 ◽  
Vol 124 (4) ◽  
pp. 374-378 ◽  
Author(s):  
C. M. Lawrence Wu ◽  
Robert K. Y. Li ◽  
N. H. Yeung
Keyword(s):  
Impact Damage ◽  
Impact Resistance ◽  
High Energy ◽  
Bending Test ◽  
Conductive Adhesives ◽  
Energy Impact ◽  
Split Hopkinson ◽  
Post Impact ◽  
Impact Bending ◽  
The Impact

Isotropic conductive adhesives (ICA) have been considered as replacement materials for lead-tin solder alloys. In this paper, the post-impact shear strength of ICA surface mount (SM) joints was obtained experimentally and compared with that of SM lead-tin joints. The dynamic impact energy was provided in the form of three-point bending on the PCB using equipment called the split Hopkinson bar. Strain rates of over 4000/s were used for the impact bending test. The action of impact bending was used to simulate the effect on the PCB and the interconnection as a result of high energy impact on an electronic equipment. Shear test was then performed to examine the change in strength of the ICA joints as a result of impact damage. It was found that the SM ICA joints failed due to impact at a strain rate just over 4000/s. Microstructural examination carried out using a scanning electron microscope revealed that the interface between the ICA and copper pad on the PCB was the weakest region of the joint.

Influence of the Cellulose and Soft Wood Fibres on the Impact and Tensile Properties in Polypropylene Bio Composites

2021 ◽  
Vol 903 ◽  
pp. 134-139
Author(s):  
Jānis Zicans ◽  
Remo Merijs Meri ◽  
Tatjana Ivanova ◽  
Andrejs Kovalovs ◽  
Piotr Franciszczak
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Resistance ◽  
Tensile Modulus ◽  
Response Surfaces ◽  
Design Parameters ◽  
Cellulose Fibres ◽  
Highest Weight ◽  
Weight Content ◽  
The Impact

Investigation presents an experimental study of mechanical properties of hybrid bio-composites made from man-made cellulose fibres and soft wood microfiller embedded into polypropylene homopolymer matrix at different weight contents. Mechanical properties such as elastic modulus, tensile strength, and impact resistance of the reinforced composites determined for various total weight contents of both biobased fillers were used as the design parameters. The problem was solved by planning the experiments and response surfaces method. The results demonstrate that using the both filler types enhance the mechanical properties. The tensile modulus increases by ~115%. The bio-composite with the highest weight content of man-made cellulose fibres and the lowest content of soft wood microfibers possesses maximum tensile strength (more 66 MPa). Addition of man-made cellulose fibres demonstrate a significant influence on the impact resistance of the investigated composites.

scholarly journals Impact Resistance of Plain and Twill Fabric in GFRP Measured by Active Thermography

2018 ◽  
Vol 27 (5) ◽  
pp. 096369351802700 ◽  
Author(s):  
G. Strugala ◽  
M. Landowski ◽  
M. Zaremba ◽  
J. Turowski ◽  
M. Szkodo
Keyword(s):  
Impact Energy ◽  
Impact Damage ◽  
Impact Resistance ◽  
Damage Area ◽  
Plain Weave ◽  
Active Thermography ◽  
Glass Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
The Impact ◽  
Twill Weave

This paper discusses the impact resistance of glass-fibre reinforced polymer (GFRP) composites depending on the type of reinforcement – plain or twill weave. The values of impact energy were: 3J, 10J and 15J. Specimens featuring twill weave transferred higher force during the impact as compared with plain weave specimens. It was observed that an increase of impact energy was accompanied by an increase of the disproportion in transferred forces, in favour of twill weave specimens. Impact damage (in both types of weave) occurring as a result of 3J impact was undetectable with active thermography method. The damage area measured by means of active thermography for impact energy values equal to 10J and 15J proved that the type of reinforcement significantly influences the impact resistance of a composite. This has been justified by smaller damage areas with high spot intensity of damage in plain weave specimens and highly dispersed damage with lower intensity in twill weave specimens.

scholarly journals Strength and Fracture Toughness of Hardox-400 Steel

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 508 ◽  
Author(s):  
Dzioba ◽  
Pała
Keyword(s):  
Fracture Toughness ◽  
Numerical Calculation ◽  
Local Stress ◽  
High Strength ◽  
Experimental Tests ◽  
Material Strength ◽  
Stress And Strain ◽  
Low Carbon ◽  
Width Measurements ◽  
Stretch Zone Width

This paper presents results of strength and fracture toughness properties of low-carbon high-strength Hardox-400 steel. Experimental tests were carried out for specimens of different thickness at wide temperature range from −100 to 20 °C. The dependences of the characteristic of material strength and fracture toughness on temperature based on experimental data are shown. Numerical calculation of the stress and strain distributions in area before crack tip using the finite element method (FEM) was done. Based on results of numerical calculation and observation of the fracture surfaces by scanning electron microscope (SEM), the critical local stress level at which brittle fracture takes place was assessed. Consideration of the levels of stress and strain in the analysis of the metal state at the tip of the crack allowed to justify the occurrence of the brittle-to-ductile fracture mechanism. On the basis of the results of stretch zone width measurements and stress components, the values of fracture toughness at the moment of crack initiation were calculated.

A Smart Polymer Composite for Repeatedly Self-Healing Impact Damage in Fiber Reinforced Polymer (FRP) Vessels

2011 ◽  
Author(s):  
Jones Nji ◽  
Guoqiang Li
Keyword(s):  
Polymer Composite ◽  
Impact Damage ◽  
Glass Fibers ◽  
Shape Memory Polymer ◽  
Impact Resistance ◽  
Three Dimensional ◽  
Polymer Composite Material ◽  
Self Healing ◽  
Repeated Impact ◽  
The Impact

This paper investigated the impact properties of a novel polymer composite material with a potential to repeatedly self-heal impact damage in FRP vessels. The composite was fabricated by first dispersing copolyster thermoplastic particles in a shape memory polymer (SMP) matrix, and then reinforcing the material with three-dimensional (3D) woven glass fibers. Specimens of the reinforced composite with dimensions of 152 mm × 101 mm × 12.7 mm were produced by machining and divided into two groups (G1 and G2). G1 specimens were subjected to several impact/healing test cycles with 42 J of impact energy. G2 specimens were subjected to repeated impact test cycles with no healing at the same energy level. A third group of specimens without thermoplastic particles (G3), with identical dimensions as G2 was also produced and tested in a similar manner as G2 to evaluate the effects of thermoplastic particles on impact resistance. G2 specimens were perforated at the 40th impact while G3 specimens were perforated at the 27th impact. G1 specimens lasted an additional 9 rounds of impact to a total of 49 impacts compared to G2 specimens.

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