Most of his work involves both analysis and experiments. He is presently also involved in smart structure design on developing technologies for health monitoring of composite structures and actively controlling the response of the structures. Professor Christensen's research is concerned with the mechanics of materials. The behavior of polymers and polymeric fiber composites are areas of specialization. Of particular interest is the field of micro-mechanics which focuses upon materials' functionality at intermediate length scales between atomic and the usual macro scale.
Applicable techniques involve the methods of homogenization for all types of composite materials.
The intended outcomes of his research are useful means of characterizing the yielding, damage accumulation and failure behavior of modern materials. These involve satellite control of attitude and translation and the development of instruments of extraordinary precision and accuracy. In GP-B gyroscopes will be orbited and compared to stars to an accuracy of less than a milliarcsecond. In STEP the orbital performance promises improvements of a million in testing the equivalence of inertial and gravitational mass. To simultaneously provide high time availability, the system must automatically compensate for any such faults.