Compressor fluids under pressure: unexpected effects

WHY

Air conditioner compressor fluids have to prevent friction and wear under elevated gas pressure.  Standard Pin&Vee Block tests with gas 'bubbling' through the lubricant do not correlate with field behaviour, especially with CO2 as the cooling medium.  Another simulation with pressurized gas is needed.  We selected the Falex Block on Ring configuration, as it also recreates the line contacts and is able to work at higher speed than the Pin&Vee block machine.

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  2108 Hits

High speed sliding behavior of polymer coatings

WHY

Nowadays polymer based coatings are applied in all walks of life, due to their excellent corrosion resistance, low friction and cost, good surface finish, molding ability and low density. However, one of the main issue of these coatings is their relatively poor performance in terms of wear. Especially, when sliding under high speeds, frictional heating can lead to a softening of the coating and accelerate the wearing-off process. Evaluating the high speed sliding performance of polymer coatings is a key issue in many applications.     

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  2002 Hits

Measuring the friction of surgical sutures

WHY

Surgical suture, holding body tissue together after an injury or surgery, is a complex product.  The thread can be surface treated or coated for a number of reasons. One of them is to facilitate the insertion through tissue, the other to hold the knots tightly.  Friction of the suture over skin, is thus important to control.  Measuring skin-suture friction allows improvement of these threads and their surface treatment.

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  1977 Hits

Simulation of wear in roll-slip contacts

WHY

The steering system of cars is based on a rack and pinion system. Over time, the metal on these gears wears out, resulting in a loose fitting. Some other applications also make use of a rack and pinion system to translate a rotary drive motion into a linear displacement.  The wear and tear of such systems occurs through a roll-slip mechanism. Therefore a tribological method needs to be developed to simulate such roll-slip contacts and their failure mechanisms.

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  1945 Hits

Pre-screening the tribological properties of shock absorbers

WHY

Shock absorber component testing is expensive and time-consuming and this is a limiting factor in developing new materials for this application. There is a need to develop a pre-screening method to get a quick but accurate evaluation of the tribological behavior of materials, without losing too much correlation with the actual conditions (geometry, wear mechanism, load, speed, number of cycles etc.).

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  1929 Hits

Fast screening polymer coatings on cables

WHY

Various types of polymers can be used on steel cables, to provide a controlled-friction and noise-reducing coating when used on pulleys.  An efficient way to prescreen the behaviour of different types of polymers, in terms of frictional stability and durability, is needed.

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  1927 Hits

Synergism between corrosion and wear

WHY

Examples of corrosion are found in many industrial applications ranging from aeronautical, automotive, naval, and the construction industry over home appliances, water systems, pipelines, and ‘bio’ applications. Corrosion phenomena can be significantly accelerated by the simultaneous occurrence of a mechanical load on the surface: the formation of cracks and surface defects, along with surface strain and stress fields lead to faster diffusion of corrosive ions or the destruction of protective layers (depassivation). Thus there is a need to understand the synergy between wear and corrosion.

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  1902 Hits

Tackiness of industrial greases: a quantitative method

WHY

Lubricating greases are used in various industrial fields ranging from food, transportation, aeronautical, construction, mining and steel industry. The aim is to decrease frictional forces and to protect industrial components from wear and/or corrosion damage. Their performance depends on interaction properties like adherence to the substrate, cohesion or consistency, and tackiness. However, up to date there is no established quantitative methodology that can be easily applied to efficiently and accurately evaluate the adhesion and tackiness of a grease.

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  1895 Hits

Seizure or galling resistance of materials at high speeds

WHY

In reality, due to a misalignment, vibrations or other reasons high speed pump rotors can come in contact with the stator, leading to a catastrophic failure.  This failure is a result of severe shearing of the contacting surfaces. However, the existing ASTM Galling method (G 196), is performed at very high pressures and very low speeds, and does not simulate the “actual” conditions met at high speeds.

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  1862 Hits

Abrasion by powders during powder processing

WHY

One issue in the pharmaceutical industry, is the abrasion of processing components for pressing the powders. The intensity of the abrasion phenomena strongly depends on the composition and size of the processed powders. Up to date there is no fixed procedure on how to evaluate such abrasion phenomena, in conditions that simulate the realistic process.

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  1826 Hits