Applications of reciprocity,electronic holography and shearography in statics

This paper illustrates the use of reciprocity in electronic-holography experiments to determine unknown forces or couples acting on a mechanical structure. Electronic holography and electronic shearography are simple, fast and contact-free methods for the measurement of deformation fields or gradients of deformation fields, both for static and sinusoidal loadings. From a first measurement, the deformation field of the structure for a known force is determined. In a second experiment, the deformation field for the unknown quantity is measured. Reciprocity is then used to determine the unknown quantity. These optical methods are useful tools for the understanding of reciprocity.