Guy Ropes Research Articles

Metallurgical failure analysis of a Guy rope assembly

A Guy rope assembly, used in stabilising a steel lattice transmission structure, failed during a heavy windstorm. The assembly was in service for over three decades. We were given the mandate to determine the reasons for the failure of the assembly and to suggest measures to prevent such failures from occurring. The study involved the in-depth examination of the chemical composition, microstructures, mechanical properties and fracture morphologies of carefully sectioned specimens. Results indicated that the failure of the Guy assembly is due to the failure of the tube housing the wire rope. Failure occurred due to local microstructural weakness (decarburization and unusually large ferrite grain size) of the tubing. Fractography indicated that failure is due to tensile overload and the mechanism of failure is micro void coalescence (MVC). Wire rope of the Guy Assembly appears to perform well. It bends to accommodate the load without breaking. Its composition corresponds to that of AISI 1080. The tubing and the end plates were low carbon structural steels corresponding to grade 1012 and 1015, respectively and lacked the high strength–toughness needed to withstand the dynamic loading resulting from the heavy winds. To solve this inherent weakness of these conventional low carbon structural steels the adoption of modern strong, tough, weldable HSLA steels has been suggested.

Paradoxical muscle contractions and the neural control of movement and balance

Paradoxical muscle contractions and the neural control of movement and balance

Electromagnetic inspection of wire ropes and strand-supported structures

For in excess of 25 years, the author has been deeply involved in the non-destructive inspection of wire rope and strand, design and development of wire rope and strand testing equipment and various methods of rope inspection including electromagnetic and visual (remote video). Many of the guyed flare stacks and wire rope or strand-supported structures in use in the US and overseas refineries, pipelines and chemical plants were erected in the 1950s, 60s and 70s. Many were built even earlier. While many of the components of these structures have been routinely inspected by various methods of testing, the wire rope and strand that support and hold these structures in position have, typically, been taken for granted and only elementary visual inspections have been performed. Wire rope and strands in sedentary environments deteriorate and lose their working capability due to many factors. These factors exist both internally and externally. This paper describes many of these factors for deterioration and the method used to detect corrosion, broken wires, abrasion, etc. Explanations as to how the instrumentation works and how the acquired data is used to estimate remaining strength is also included in the paper. Procedures for the inspection of guy ropes. strands and their related fittings are also covered in the paper.

Ultra low cost solar cookers: design details and field trials in Tanzania

A family-sized ultra low cost solar cooker has been developed. The hot box style cooker is designed to be built on site by the users with minimal tools, skills or special materials. It consists of a shallow 1 m 2 square hole in the ground, insulated with straw and lined with adobe (mud and straw), a glass or plastic roof, and a 1 m 2 aluminised plastic reflector with guy ropes for adjustment. An insulated fabric door allows access to the oven; pots are slid in, onto a metal base plate. The cost is about £8. The cooker has been shown to provide cooked food for 10–12 people on clear days with meals around midday and dusk (assuming 0.4 kg dry weight of food per person daily). A four litre load of water can be brought up to cooking temperature (80°C) in 60–70 min. The adobe linear provides some thermal mass to even out temperature swings in cloudy weather. The cooker was developed at the Sunseed Trust's Spanish Project, Sunseed Desert Technology. It is being field tested by Sunseed in Tanzania. The paper reports on technical results and observations on how the cooker technology can best be integrated into this particular African context.

Eversion of difficult ileostomies by guy rope suture technique

In the creation of a permanent ileostomy, a fully everted nipple ensures a good fit of the stomal appliance. In normal bowel segment this may not pose a problem, but forceful attempts at eversion in diseased, thickened, and friable bowel may result in damage to the bowel segment. In order to prevent this, we developed a technique that uses the guy rope principle to evert the necessary length of bowel. The technique described in this article may also be used to evert healthy segments of bowel during creation of a permanent ileostomy.