460 research outputs found
An initial investigation on the potential applicability of Acoustic Emission to rail track fault detection.
In light of recent accidents in the rail industry, the assessment of the
mechanical integrity of rail-track is of vital importance. This encompasses the
integrity of the track due to rolling contact fatigue and surface wear. Whilst
numerous techniques are employed for crack detection, several defects have
clearly been missed. In Europe, more than 100 rails are broken each year and
rail maintenance costs within the European Union is estimated at 300-million
Euros annually [Inst Mech Engrs 216 (2001) 249]. The derailment of a train at
Hatfield in October 2000 is a tragic example of a fractured rail going
undetected. This paper presents an experimental study on the applicability of
Acoustic Emissions (AE) for rail-track defect diagnosis. An experimental test-
rig was employed for this programme. This allowed for a surface defect to be
seeded onto the test-rig. The investigation presented is part of an on-going
attempt to develop the non-destructive technique of AE for assessing the surface
integrity of rail-track. The AE technique is not new but the application in this
particular instance is unique. It is concluded that the AE technique offers a
complementary tool for rail track defect detection
Observations of acoustic emission activity during gear defect diagnosis.
It is widely recognised that acoustic emission (AE) is gaining ground as a non-
destructive technique (NDT) for health diagnosis on rotating machinery. The
source of AE is attributed to the release of stored elastic energy that
manifests itself in the form of elastic waves that propagate in all directions
on the surface of a material. These detectable AE waves can provide useful
information about the health condition of a machine. This paper reports on part
of an ongoing experimental investigation on the application of AE for gear
defect diagnosis. Furthermore, the possibility of monitoring gear defects from
the bearing casing is examined. It is concluded that AE offers a complimentary
tool for health monitoring of gears
Mechanical evolution of the rotating biological contactor into the 21st century.
This paper presents a review on the evolution of the mechanical design of
rotating biological contactors (RBCs) within the UK. The findings documented
have been taken from the biggest mechanical survey on RBCs ever undertaken
worldwide and focuses on 300 operational units. The paper looks at the main
components of the RBC and discusses the evolution of each member. Mechanical
deficiencies associated with each design are briefly presented, giving an
insight into reasons for improvements. This is the only known document that
details changes in design philosophy employed over the last 30 years, with
illustrative examples. For the purpose of this review, the mechanical evolution
of the RBC is focused on three primary sections: media panel designs, media
support structures, and auxiliary support systems including bearings, power
units, and transmission systems. It is shown that the evolution of media panels
has largely been directed by economies of manufacture and operational
requirements. However, advances in the mechanical design of the RBC supporting
structure, while dependent on media type, are largely influenced by overcoming
known mechanical deficiencies as well as increasing operational life. This paper
depicts the current technology and practice of UK-based manufacturers and
details reasons for mechanical deficiencies
- …