A test bed is only as accurate as the sensors it uses to collect data. In the case of engine dynamometers, the test environment is a very ‘noisy’ place, with many sources of vibration and electromagnetic interference (EMI) present, all of which can skew sensor readings. This is a particular issue when it comes to sensors such as strain gauges and thermocouples, which have very low output signals. Whereas sensors like pressure transducers can have an output voltage of 1-10 V, the...
Accurate measurement and testing of parts with complex internal features can be fraught with difficulties. Often, the only way to achieve accurate checking is to sacrifice a part to destructive testing in order to ensure correct internal tolerances are being met. However, even this cannot ensure complete control over the quality of finished parts. For example, the make-up of parts produced using SLS (selective laser sintering) processes can vary from one component to the next, so a means...
At the moment, most dynamometer torque sensors use either strain gauges or, in more advanced applications, magneto-elastic sensors to measure output torque. However, in recent years new sensors for torque measurement based on Surface Acoustic Wave (SAW) transducers have been developed that have potential uses in dynamometer applications. The sensors work by measuring changes in SAW properties across a substrate as the stress within the substrate varies. In its simplest form, a SAW...
Traditional flow benches for measuring cylinder head port flow rates are a useful tool for determining how efficient a particular port design is in terms of basic airflow characteristics. However, they are limited in that they do not show how a particular geometry affects other factors such as mixture suspension or distribution within the port. Aspects such as these can be investigated using modern CFD techniques, although this is still a very specialised field and an avenue not available...
In a previous RET-Monitor we looked at testing the material properties of composites, so this month we will investigate a machine that is particularly suited to tensile testing of such materials, the video extensometer, which can provide an accurate measurement of deformation and failure while also providing invaluable visual data on the method of failure. Material stress is normally calculated by measuring the specimen’s cross-sectional area and relating this to the measured load...