The design and operation of an aircraft, a railway, and a nuclear power station that include either safety-critical or safety-related systems require a proof that its safety is assured. The process providing this proof is called certification. This paper suggests an iterative FPGA implementation and iterative certification concept for FPGA-based systems to provide design-time adaptability while the complexity is still kept low to ease certification.The practical evaluation of this concept demonstrates that reuse at implementation level of a previously implemented part is to 100% usable for iterative certification. Regarding the resource utilization and complexity, the evaluation shows that there are potential savings in resource utilization and complexity compared to conventional run-time configurable designs. Iterative certification reduces the recertification of a whole design to a recertification of the changed part only and a verification tool qualification. It is shown that tool qualification can be accomplished with relatively moderate effort. Therefore, the presented concept substantially eases the certification process when using modular design and building block reuse.

The phase transformation of thermal shape memory alloys (SMAs) can be described by surfaces in a temperature-stress-strain space. A novel experimental technique for the thermomechanical characterization of thin SMA wires allows to scan these surfaces with high resolution. Each experimental run uses a sequence of experimental conditions to traverse the phase transformation surfaces on a different path from “full martensite” to “full austenite” and vice versa. At all times, stress and strain are kept within the limits specified for the use of the SMA wire in actuators. The wire is heated externally through a silicon oil bath, which ensures a controlled and homogeneous temperature of the specimen. The experimental setup is designed to minimize the impact of the large oil temperature variations on measurement results. Experimental results are shown for both mechanical contraction and electrical resistance, each of which forms consistent surfaces for the phase transformation. Measurements for external heating in the oil bath are compared to electrical heating in air.