The Kirkaldy Testing Museum is a museum in Southwark, south London, England, in David Kirkaldy's former testing works. It houses Kirkaldy's huge testing machine, and many smaller more modern machines. It is open on the first Sunday of each month.
The building at 99 Southwark Street became a listed building in 1971, and was promoted to Grade II* in June 2014.
Background
Kirkaldy was born in Dundee in 1820, and educated at Edinburgh University. He worked at Napier shipbuilding works from 1843, where he became Chief Draughtsman and Calculator. He left in 1861 and over the next two and a half years studied existing mechanical testing methods and designed his own testing machine. William Fairbairn had pioneered tensile strength measurement as well as assessing creep and fatigue on large structures as well as small.
Entirely at his own expense, Kirkaldy commissioned his machine from the Leeds firm of Greenwood & Batley, closely supervising its production. Aggrieved over the slow rate of manufacture, after 15 months he had the machine delivered to Southwark still unfinished, in September 1865.
Universal Testing Machine
The testing machine is long and weighs some . It works horizontally, the load applied by a hydraulic cylinder and ram. The working fluid is water not oil. The load is measured by a weighing system consisting of a number of levers with the final one carrying a jockey weight. The operator lets water into the hydraulic cylinder and as the pressure and hence load on the test piece increases the jockey weight is wound along to balance the hydraulic load. As it is wound it moves along a graduated scale and when the object under test fails the number on this scale is noted and multiplied by the weight to give the failure load.
The weight can be varied in increments of using slotted plates on a hanger. On the lower scale this reads up to , and up to can be put onto the hanger. A separate jockey weight system above this one allowed the machine to measure loads of up to .
The machine is kept in working order at the Kirkaldy Museum in Southwark. Problems can occur with the gasket which seals the single hydraulic cylinder. The gasket is in the original material, leather, rather than a more modern material. Originally the London Hydraulic Power Company supplied the high-pressure water, but now the museum uses an electric pump. When breaking specimens for visitor demonstrations a load not exceeding is used.
Kirkaldy also developed methods for examining the microstructure of metals using optical microscopy. It involved cutting sections, polishing the sections and then etching to reveal different constituents.
Notable tests
The Kirkaldy works also tested components for the Eads Bridge across the Mississippi River in St. Louis, USA, which was completed in 1874, for Hammersmith Bridge (1887), the old Wembley Stadium (1923), and for the Skylon that was built for the nearby Festival of Britain in 1951. It also helped accident analysis by testing materials from structures that failed, including the Tay Bridge Disaster of 1879 and the BOAC Flight 781 De Havilland Comet crash of 1954.
Tay bridge disaster
In 1880 Kirkaldy tested many samples from the first Tay railway bridge for the official Inquiry into the collapse of the bridge's central section on 28 December 1879. He confirmed that the wrought iron tie bars failed at their connections to the cast iron columns of the bridge, when he tested intact tie bars with complete lugs still attached. The attachments were cast iron lugs which fractured at the bolt holes, and after the disaster numerous fractured lugs were found lying on the piers. The critical strengthening elements were much weaker than had been supposed by Thomas Bouch, the engineer of the first bridge. They failed at about tensile load rather than the specified , and were a prime cause of the collapse of the bridge.
Since Kirkaldy tested several samples of each of the lower and upper lugs, he was able to show that they exhibited a range of strengths, the lowest results being caused by defects like blow holes in the cast metal. Thus some of the upper lugs were actually weaker than the strongest lower lugs, an observation confirmed by damage shown on the remains left on the piers after the disaster. He tested the wrought iron tie bars themselves, and they proved tough, as specified, although only slightly stronger than the cast iron lugs to which they were attached.