A unique strain gage based method is developed to identify the magnitude and location of a load on a slender beam with non-homogeneous material, variable cross sections, and pinned, firm rest, soft rest, pinned-fixed, and fixed boundary conditions. Four uniaxial strain gages are mounted to the bottom surface of the beam, and the bending moment diagram of the beam can be constructed using measured strains on the beam. By combining individually scaled strain gage outputs, the magnitude and location of the load can be accurately identified. The strain gage based force transducer methodology is experimentally validated on prismatic beams with firm rest, soft rest, firm rest-fixed, and fixed boundary conditions, and a continuously tapered beam with rest boundary conditions. The force transducer methodology is independent of the boundary conditions of the beam and the error from strain gage drift due to uniform thermal expansion on a prismatic beam can cancel out.

Unique strain gage based methods are developed to identify magnitudes and locations of multiple loads on a slender beam. Four uniaxial strain gages mounted to the bottom surface of the beam create a force transducer capable of identifying the magnitude and location of a load inside the weight area. For the case of multiple loads separated by two or more strain gage locations, uniaxial strain gages forming multiple force transducers can still identify the magnitudes and locations of all the loads. However, this creates an ill posed problem for loads separated by only one strain gage location. A new method has been developed using two shear gages mounted on the neutral axis of the beam, one on each side of a load, to identify the magnitude of the load in this case. A combination of two uniaxial strain gages and two shear gages, with one uniaxial strain gage and one shear gage at the same location on each side of a load, can be used to identify the location of the load. The strain gage based methods are experimentally validated on a prismatic beam with rest boundary conditions.

High-pressure hydraulic hoses are used throughout industry to transmit fluid power. The current state of the art in hose replacement consists of two strategies; these are (1) replacement upon failure and (2) time-based replacement. For the replacement upon failure method, end users inspect hoses and either replace when there is obvious physical damage or the hose has burst and allowed the release of fluid under high pressure. Hose users that employ time-based replacement cycles often collect data and either subjectively or statistically choose a replacement frequency intended to prevent unexpected failures. Engineers at Eaton Corporation worked with Purdue University to develop an alternative. A novel hose construction using two conductors with an isolating layer provides a component in an electrical circuit which can be monitored to determine the status, or health, of a hose in operation. The first step in this development was the realization that hose failure is a process and not an event. By tracking a hose’s electrical signature and characterizing the change that occurs when the internal structure begins to break down, a user is alerted prior to a catastrophic hose failure. Eaton is developing notification systems capable of both monitoring the hose’s electrical signature and alerting an equipment user prior to unexpected failure. The system requires direct electrical connection to the hose fitting for monitoring. There are currently two strategies in development, a wired system and a wireless system. The wired system uses a remote diagnostic unit with cables running to each hose assembly to query the hose and alert an equipment user directly. The wireless system employs battery-powered sensors installed on a hose assembly which communicate with a gateway located nearby. When a hose approaches its end of life a warning is issued by illuminating a warning light or issuing a remote warning through a cellular or wireless network. There are significant gains in the ability to prevent hydraulic hose failures. These unexpected incidents lead to downtime, damage to equipment, environmental damage, and serious personal injury. Additionally, using this advanced warning system allows users to use nearly a hose’s entire life. This improves asset utilization considerable when compared to the useful life sacrificed by using time-based replacement schedules. This technology will reduce operating costs and prevent downtime, environmental incidents, and the threat of personal injury present when hydraulic hose fails.