The Small Business Innovation Research (SBIR) Phase I project seeks to develop a welding technology for joining low permeability polymer insulation (LPPI) foams prior to applying a composite overwrap. The syntactic foam is flexible over a wide range of operating temperatures, and provides a useful combination of thermal protection, low hydrogen permeability, and compressive strength. The major steps for the proposed in-situ welding process consist of (i) using pre-formed strips of uncured LPPI as feedstock, (ii) developing the means for preheating the tapered joint between the pre-molded LPPI sheets, (iii) developing the means and method for preheating the LPPI feedstock, and (iv) developing the means and method for melting and curing the LPPI weld.
The proposed technology will enable the fabrication of large-scale cryogenic tanks for hydrogen storage and aerospace applications. In addition, the technology has the potential to reduce microcracks in the composite due to thermal cycling from cryogenic to elevated temperatures.
