Patent ID: 8544338

Claim:
A device which provides cyclic load testing of a sample, comprising: (a) an internal load frame with a first and second end and comprising at least one member; and (b) a first external load frame with a first and second end and comprising at least one member, wherein the first external load frame substantially encloses the internal load frame over at least a portion of its length; and (c) at least one guiding interface between the internal and first external load frames by which the said load frames are maintained in a substantially coaxial alignment, either by direct contact between the two load frames, or indirectly acting through a guiding interface in the sample; and (d) means for connecting to the sample to create a load path through the sample, comprising: (i) means for connecting a first location on the sample to the first end of the first external load frame; and (ii) means for contacting a second location on the sample with the first end of the internal load frame; and (e) at least one solid state energy conversion actuation system extending from the second end of the first external load frame to the second end of the internal load frame comprising: (i) a solid state material system which undergoes deformations in response to application of energy, with the orientation of the solid state actuation material and the application of energy such that the deformations occur predominantly in the direction of the desired loading; and (ii) means for connecting the at least one solid state energy conversion actuation system to the second end of the adjacent load frames; and (f) at least one prestressing arrangement for the at least one solid state energy conversion actuation system extending between the load frames comprising at least two members wherein: (i) a first and a second member which are joined by an adjustable length connection by which the complete load train represented by the load frames and the sample assembled together can be preloaded to put the at least one solid state energy conversion actuation system extending between said load frames in compression in its neutral state; and (ii) said first and second members are members of the at least one member of one of the load frames.