320 Observation of the fracture behavior by the impact test of A1050-ADC12 functionally graded porous aluminum

Eco-friendly cushioning materials were made with thermomechanical pulps (TMPs) from waste woods collected from local mountains in Korea, using a suction-forming method without physical pressing. The TMP cushions had superior shock-absorbing performance, with lower elastic moduli than expanded polystyrene (EPS) or molded pulp. Even though the TMP cushions made using various suction times had many voids in their inner fiber structure, their apparent densities were a little higher than that of EPS and much lower than that of molded pulp. The addition of cationic starch contributed to an increase in the elastic modulus of the TMP cushions without increasing the apparent density, an effect which was different from that of surface sizing with starch. In the impact test, the TMP cushions showed a more ductile pattern than the brittle EPS. The porosity of the TMP cushion was a little less than that of EPS and much greater than that of molded pulp. The porous structure of the TMP cushions contributed to their excellent thermal insulating capacity, which was equivalent to that of EPS. In summary, the TMP packing cushions showed great potential for surviving external impacts during product distribution.

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Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

Journal of Applied Volcanology ◽

10.1186/s13617-021-00105-8 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Hiroyuki Yamada ◽

Kohei Tateyama ◽

Shino Naruke ◽

Hisashi Sasaki ◽

Shinichi Torigata ◽

...

Keyword(s):

Impact Energy ◽

Impact Test ◽

Impact Resistance ◽

Protective Layer ◽

High Strength ◽

Steel Plates ◽

Corrugated Plates ◽

Shelter Construction ◽

The Impact ◽

Ballistic Ejecta

AbstractThe destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

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A Refined Theory for Bending Vibratory Analysis of Thick Functionally Graded Beams

Mathematics ◽

10.3390/math9121422 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1422

Author(s):

Youssef Boutahar ◽

Nadhir Lebaal ◽

David Bassir

Keyword(s):

Beam Theory ◽

Functionally Graded ◽

Effective Characteristics ◽

Hyperbolic Function ◽

Transverse Displacement ◽

Refined Theory ◽

Distribution Law ◽

Fg Beam ◽

The Impact ◽

Beam Theories

A refined beam theory that takes the thickness-stretching into account is presented in this study for the bending vibratory behavior analysis of thick functionally graded (FG) beams. In this theory, the number of unknowns is reduced to four instead of five in the other approaches. Transverse displacement is expressed through a hyperbolic function and subdivided into bending, shear, and thickness-stretching components. The number of unknowns is reduced, which involves a decrease in the number of the governing equation. The boundary conditions at the top and bottom FG beam faces are satisfied without any shear correction factor. According to a distribution law, effective characteristics of FG beam material change continuously in the thickness direction depending on the constituent’s volume proportion. Equations of motion are obtained from Hamilton’s principle and are solved by assuming the Navier’s solution type, for the case of a supported FG beam that is transversely loaded. The numerical results obtained are exposed and analyzed in detail to verify the validity of the current theory and prove the influence of the material composition, geometry, and shear deformation on the vibratory responses of FG beams, showing the impact of normal deformation on these responses which is neglected in most of the beam theories. The obtained results are compared with those predicted by other beam theories. It can be concluded that the present theory is not only accurate but also simple in predicting the bending and free vibration responses of FG beams.

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Dynamic fracture behavior in functionally graded piezoelectric bimaterials with interfacial cracks emanating from a circular cavity

Journal of Mechanics of Materials and Structures ◽

10.2140/jomms.2021.16.89 ◽

2021 ◽

Vol 16 (1) ◽

pp. 89-104

Author(s):

Ni An ◽

Ming Zhao ◽

Tianshu Song ◽

Haizhu Pan

Keyword(s):

Dynamic Fracture ◽

Fracture Behavior ◽

Functionally Graded ◽

Circular Cavity ◽

Interfacial Cracks ◽

Functionally Graded Piezoelectric

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Experimental Determination of Dynamic Characteristics of a Full Size Gas Turbine Tilting-Pad Journal Bearing by an Impact Test Method

13th Biennial Conference on Mechanical Vibration and Noise: Modal Analysis, Modeling, Diagnostics, and Control — Analytical and Experimental ◽

10.1115/detc1991-0397 ◽

1991 ◽

Author(s):

S. H. Chan ◽

M. F. White

Keyword(s):

Gas Turbine ◽

Impact Test ◽

Journal Bearing ◽

Estimation Procedure ◽

Response Spectra ◽

Test Method ◽

Full Size ◽

Tilting Pad ◽

Tilting Pad Journal Bearing ◽

The Impact

Abstract Measurements have been taken on an experimental rotor-bearing test rig which consists of a full size gas turbine shaft supported by two five-pad tilting-pad journal bearings. The impact test method was applied by exciting one end of the shaft in-situ by means of a hammer blow. Impact forces and response displacements were collected and analysed with suitable corrections for runout effect. Averaged frequency response spectra thus obtained were used in a parameter estimation procedure to calculate the dynamic coefficients of the tested tilting-pad journal bearing. An analytical single degree-of-freedom model was employed and one of the input parameters in the mechanical model, the effective mass, was found to significantly influence the estimated results. The measured stiffness and damping coefficients are compared with results predicted by a bearing design program. Possible sources of discrepancies between experimental and theoretical results are discussed.

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A new technique for testing the impact load of thin films: the coating impact test

Metallurgical Coatings and Thin Films 1992 ◽

10.1016/b978-0-444-89900-2.50023-3 ◽

1992 ◽

pp. 102-107 ◽

Cited By ~ 1

Author(s):

O. Knotek ◽

B. Bosserhoff ◽

A. Schrey ◽

T. Leyendecker ◽

O. Lemmer ◽

...

Keyword(s):

Thin Films ◽

Impact Test ◽

Impact Load ◽

New Technique ◽

A New Technique ◽

The Impact

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The Effect of Layers and Bullet Type on Impact Properties of Glass Fibre Reinforced Polymer (GFRP) Using a Single Stage Gas Gun (SSGG)

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.564.428 ◽

2014 ◽

Vol 564 ◽

pp. 428-433 ◽

Cited By ~ 3

Author(s):

S.N.A. Safri ◽

Mohamed Thariq Hameed Sultan ◽

N. Razali ◽

Shahnor Basri ◽

Noorfaizal Yidris ◽

...

Keyword(s):

Impact Energy ◽

Glass Fibre ◽

Impact Test ◽

Single Stage ◽

Gas Gun ◽

Reinforced Polymer ◽

Glass Fibre Reinforced Polymer ◽

Fibre Reinforced Polymer ◽

Glass Fibre Reinforced ◽

The Impact

The purpose of this work is to study the best number of layer with the higher impact energy using Glass Fibre Reinforced Polymer (GFRP). The number of layers used in this study was 25, 33, 41, and 49. The impact test was performed using Single Stage Gas Gun (SSGG) for each layers given above with different bullets such as blunt, hemispherical and conical bullets. The gas gun pressure was set to 5, 10, 15 and 20 bar. All of the signals captured from the impact test were recorded using a ballistic data acquisition system. The correlation between the impact energy in terms of number of layer and type of bullet from this test are presented and discussed. It can be summarise that as the number of layer increases, impact energy also increases. In addition, from the results, it was observed that by using different types of bullets (blunt, hemispherical, conical), there is only a slight difference in values of energy absorbed by the specimen.

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Effect of Filler Compositions on the Mechanical Properties of Bamboo Filled Polyester Composite

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.879.90 ◽

2014 ◽

Vol 879 ◽

pp. 90-95 ◽

Cited By ~ 2

Author(s):

Abdul Rahman Noor Leha ◽

Nor Amalina Nordin

Keyword(s):

Mechanical Properties ◽

Flexural Strength ◽

Impact Test ◽

Compression Molding ◽

Engineering Applications ◽

Maximum Value ◽

Polyester Composite ◽

Bamboo Powder ◽

Flexural Tests ◽

The Impact

Biocomposite from bamboo powder was fabricated by compression molding technique. The objective of this study was to investigate the mechanical properties of bamboo compounded with epoxy with different ratio. Tensile and flexural tests were done to characterize its mechanical properties. It was observed that the strength of bamboo-polyester was increased with increasing amount of bamboo powder. The tensile and flexural strength shows the highest value at 25 wt.% bamboo. However, the impact test shows the maximum value at 20 wt.% bamboo powder. These results exhibit the bamboo-polyester can be a good candidate to be used in many engineering applications

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

Volume 6: Ceramics; Controls, Diagnostics, and Instrumentation; Education; Manufacturing Materials and Metallurgy ◽

10.1115/gt2018-76116 ◽

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.

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