الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The force transducers are indispensable measuring elements in many engineering
fields that include military, construction, medical, food industries, testing,safety…etc. Building such sensors is a duty that needs heavy experience. Hence to have a sensor that has good metrological characteristics, a big amount of money has to be paid.Among the drawbacks that restrict the usage of these sensors are; each sensor has
only a limited capacity that shall not be exceeded, which might lead to its
collapse. Also, every sensor has a lower limit, below that limit, the required
tolerances are hard to achieve. Hence, it is expected that a device that can achieve
the multi-capacity concept may replace a set of force transducers both obtained
to cover a certain force measurement range.The principal aim of building a multi-capacity sensor is to provide the society of force measurement with an economical and simpler facility for force measurement. The multi-capacity force measurement system is a forcemeasuring device capable of operating at multi-force measurement ranges. The idea of building a force measurement device that has the multi-capacity feature appeared for a while in the literature.It could be concluded from the previous designs that there are two techniques to build a multi-capacity force measurement system. The first is through increasing
the stiffness of the elastic element of a force transducer. The second is through
using multi-force transducers under a certain arrangement or in a single
mechanism which allow them to work together to cover a wide range of force
measurement. The common weaknesses in the earlier designs are; difficult
designs, the majority of them are applicable to measure small forces.To achieve the multi-capacity concept, two innovative designs were proposed
during this study. To check the validity and performance of these designs, two
prototypes were implemented then tested. The metrological characteristics were
evaluated following ISO 376:2011.The first idea to achieve the multi-capacity concept is based on increasing the
stiffness of a bending ring force transducer. This could be done by adding in series a new elastic element to the sensor to increase its stiffness. Using this idea the capacity of a certain force transducer could be increased to double, five times or more depending on the stiffness of the new element added to the transducer. Based on the executed prototype at PTB, Germany, the capacity of the sensor was increased from 10 to 20 kN with amazing metrological characteristics. Considering the final evaluation results, the prototype achieves class 00 (the best
class) using two active signals. While, it achieves class 0.5 (the second-best class) based on a single active signal.The second idea is based on using a build-up system based on three elastic
elements in a radial parallel arrangement. One of the elastic elements has an active force signal while the others are dummy. Applying this system, the force could be measured up to a capacity equal to three times the capacity of a single force transducer. According to the evaluated results of the implemented prototype, the system achieves class 1 according to ISO 376:2011.