Wire Fencing (Part 1): Determinants of Wire Quality
Knotted wire fences are fabricated on specialised machines. The input material is typically galvanised steel wire. However, the quality of the input wire used by the Fence Producer is beyond control of the Machine Manufacturer. The problem is that wire strand breakages have been reported during fabrication and subsequent field erection. This is an issue for the Fence Producer because of the lost productivity, and the potential for reputation (brand) damage for both the Manufacturer and Producer. While existing standards do exist for wire, even wire that meets these standards is known to fail during fence fabrication. Thus there is a need to better understand how the quality of wire affects the manufacturabil- ity of fences, and to identify, or if necessary create, a test for wire quality that is able to be conducted by Fence Producers. In this research, samples were obtained from known good and failed fences and wire coils, and subjected to a variety of physical and metallurgical tests. These were then statistically examined and compared to the known fate of the fence, to determine the sensitivity of the test. Four potential tests were evaluated: Tensile strength (UTS), ductility, 3-point bend- ing, microstructural, impact energy, plus a fifth novel new test called linear torsional ductility (LTD). From these tests, it was evident that the linear torsional ductility test was the most sensitive and reliable indicator for wire quality. This paper is part of a collection, with companion papers examining material properties of wire, microstructure, impact energy for wire, knot performance, and the testing of whole fences.
The Corrosion Of Fence Wire...
"The investigation of which this bulletin is in part a record has been carried on with a twofold purpose in view. The first object is to furnish information to the farmer which will enable him to exercise an intelligent judgment as to the difficulties involved in the manufacture of wire fencing which shall be low in price and at the same time resistant to rust and corrosion. The second object has been to determine, with the cooperation of progressive manufacturers and metallurgists, the causes which underlie the much too rapid corrosion of modern steel wire, and, if possible, to suggest improvements in methods of manufacture by means of which the difficulties may be at least partially, if not wholly, overcome." -- p. 5
Adaptive control of systems with unknown output backlash
Adaptive control schemes for systems with unknown backlash at the plant output are developed. In the case of known backlash, a backlash inverse controller guarantees exact output tracking. When the backlash characteristics is unknown, adaptive laws are designed to update the controller parameters and to guarantee bounded input-output stability. Simulations show significant improvements of the system performance achieved by such adaptive backlash inverse controllers.<<ETX>>