Test Method for Wear Preventive Properties of Lubricating Greases Using the (Falex) Block on Ring Test Machine in Oscillating Motion

Based on the motion characteristics of mechanical oscillating parts, a wear test machine is developed with single drive biaxial rotational oscillating, which can effectively simulate multiaxial rotational oscillation of mechanical oscillating parts and take different kinds of friction couplings wear test. Based on this design, the tribological property of easy wearing material in mechanical oscillating parts is studied and corresponding sphere-block test method is established. Pilot test and demonstration are taken to evaluate the sphere-block test method from feasibility, practicality, reliability and economy aspects. The results are meeting test requirements of tribological property under the condition of composite motion.

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Effect of ultrasonic melt treatment on the tribological behavior of 7075 aluminum alloy

Materials Testing ◽

10.1515/mt-2020-621214 ◽

2020 ◽

Vol 62 (12) ◽

pp. 1243-1250

Author(s):

Fahri Vatansever ◽

Alpay Tamer Erturk ◽

Erol Feyzullahoglu

Keyword(s):

Surface Roughness ◽

Aluminum Alloy ◽

Tribological Properties ◽

Lower Surface ◽

Test Method ◽

Ring Test ◽

7075 Aluminum Alloy ◽

Melt Treatment ◽

Ultrasonic Melt Treatment ◽

Worn Surfaces

Abstract In this study, the tribological properties of 7075 aluminum alloy produced by ultrasonic melt treatment (UST) are investigated. Tribological properties of untreated and ultrasonically treated samples under dry and lubricated sliding conditions were analyzed experimentally by the block on ring test method. Worn surfaces of untreated and ultrasonically treated samples were scanned by 3D optical profilometer and analyzed to search out wear characteristics in the material. Furthermore, microstructural examinations were conducted to investigate the beneficial effects of UST on the microstructural properties of the alloy using optical and scanning electron microscopy. According to the results obtained, UST refines the α-Al phase of the alloy and disperses precipitates to grain boundaries more uniformly. Also, hardness and density of the alloy increased through the effect of UST. Due to these favorable effects, the wear resistance of the alloy increased and the worn surfaces of the ultrasonically treated samples exhibited lower surface roughness according to 3D surface roughness measurements.

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Towards a Planar Cruciform Specimen for Biaxial Characterisation of Polymer Matrix Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.24-25.115 ◽

2010 ◽

Vol 24-25 ◽

pp. 115-120 ◽

Cited By ~ 14

Author(s):

Michael R.L. Gower ◽

Richard M. Shaw

Keyword(s):

Strain Distribution ◽

Stress Raiser ◽

Test Method ◽

Image Correlation ◽

Strain Gauges ◽

Test Machine ◽

Element Analysis ◽

Full Field ◽

Cruciform Specimen ◽

Gauge Section

This paper details work undertaken towards the development of a standard test method for the biaxial response of planar cruciform specimens manufactured from carbon fibre-reinforced plastic (CFRP) laminates and subject to tension-tension loading. Achieving true biaxial failure in a cruciform specimen without the need for the inclusion of a stress raiser, such as a hole, in the gauge-section, is a subject attracting much research globally and is by no means a trivial exercise. Coupon designs were modelled using finite element analysis (FEA) in order to predict the stress and strain distributions in the central region of the specimen. An Instron biaxial strong-floor test machine was used to test the specimens. Strain gauges were used to measure the strain in the specimen arms and to assess the degree of bending. Digital image correlation (DIC) was used to measure the full-field strain distribution in the central gauge-section of the specimen and this was compared to values measured using strain gauges. The strain readings obtained from strain gauges, DIC and FEA predictions were in good agreement and showed that the strain distribution was uniform in the central gauge-section, but that strain concentrations existed around the tapered thickness zone. These regions of strain concentration resulted in interlaminar failure and delamination of the laminate propagating into the specimen arms.

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Restrained Shrinkage Behavior of Concrete under Different Environmental Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.941-944.835 ◽

2014 ◽

Vol 941-944 ◽

pp. 835-841 ◽

Cited By ~ 1

Author(s):

Zhi Tao Chen ◽

Mao Guang Li ◽

Ying Zi Yang ◽

Qi Liu

Keyword(s):

Relative Humidity ◽

Environmental Conditions ◽

Test Method ◽

Mineral Admixtures ◽

Ring Test ◽

Test Duration ◽

Restrained Shrinkage ◽

Shrinkage Cracking ◽

Higher Temperature ◽

Shrinkage Behavior

The ring test method is used to evaluate the behavior of concrete under restrained shrinkage. Four kinds of environmental conditions (20±1°C, RH60±5%; 35±1°C, RH60±5%; 50±1°C, RH15±5%; 65±1°C, RH15±5%) were designed to investigate the effect the environmental condition on the shrinkage behavior of concrete prepared with different kinds of mineral admixtures. The results show that higher temperature and lower relative humidity can increase the risk of shrinkage cracking. The addition of different mineral admixtures increases the shrinkage of concrete at room conditions. In the case of higher temperature and lower relative humidity, the addition of mineral admixtures can delay the shrinkage cracking in the test duration.

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