Nowadays electrical force transducers, in which various electrical conversion principles are applied, are widely used. Transducers for forces from 1N till 10 MN are commercially available and used for industrial as well as research purposes. They not only serve to measure forces but also for weighing purposes. Directly converting a force into an electrical signal is not possible. This must be done step by step. For instance, in a strain gauge based transducer the conversion chain is: force - stress - strain - resistance change - bridge output. At every conversion point in this chain parasatic influences can interfere with the results and may cause a loss in accuracy. To surmount the problems related to obtaining sufficient accuracy and reliability for these transducers, much research has been done allover the world in the past 35 years. As a result, new materials, new techniques, improved constructional designs and compensation circuits have been found to overcome the parasitic influences. The object of the IMEKO Conferences on behalf of the Technical Committee on Measurement of Force and Mass (TC-3) is to exchange experiences, to discuss problems and to obtain knowledge about practical applications. In this book the papers have been collected that will be discussed at the 11th International Conference on Measurement of Force and Mass. The topic of this conference is "Mechanical Problems in Measuring Force and Mass."

Designing and manufacturing structures of all kinds in an economic and a safe way is not possible without doing experimental stress analysis. The modernity of structures, with their higher reliability demands, as well as today's more stringent safety rules and extreme environmental conditions necessitate the improvement of the measuring technique and the introduction of new ones. Although theoretical/mathematical analysis is improving enormously, an example of which is the finite element model, it cannot replace experimental analysis and vice versa. Moreover, the mathematical analysis needs more and more accurate parameter data which in turn need improved experimental investigations. No one can do all those investigations on his own. Exchange of knowledge and experience in experimental stress analysis is a necessity, a thing acknowledged by every research worker. Therefore, the objective of the Permanent Committee for Stress Analysis (PC SA) is to promote the organization of conferences with the purpose disseminating new research and new measuring techniques as well as improvements in existing techniques, and furthermore, to promote the exchange of experiences of practical applications with techniques. rhis Vlllth International Conference on Experimental Stress Analysis on behalf of the PC SA is one in a series which started in 1959 at Delft (NL), and was followed by conferences at Paris (F), Berlin-W, Cambridge ( K), Udine (I), Munich (FRG) and Haifa (Isr.). Such a Conference will be held in Europe every fourth year, half-way bewteen the IUTAM Congresses.