Lightweight blast resistant container

Abstract

This invention is a novel lightweight blast resistant container. It consists of containers made of a blast resistant fiber reinforced polymer resin matrix composite. The invention employs a novel construction configuration whereby the container is created by the appropriate nesting of composite parts to create a cube, box or multi-faceted geometry. As a result of the nesting, the box like geometry exhibits characteristics that cause the geometry to behave more like a sphere than a box when subjected to internal blast pressures. Such an approach provides an optimized minimum weight solution by fully utilizing the entire material volume, whereby ultimate tensile strength can be simultaneously developed everywhere in the container.

1 . A method of making a blast resistant container constructed at least in part of a composite fiber reinforced polymer resin matrix, comprising utilizing a polymer resin with a viscosity suitable for Vacuum Infusion Processing and a shrinkage strain of at least 2% for the neat resin when fully cured.  
   
   
       2 . The method of  claim 1  wherein the resin has a viscosity less than 350 centiposes.  
   
   
       3 . The method of  claim 1  wherein the resin has a styrene content of no more than 35%.  
   
   
       4 . A method of making a blast resistant container constructed at least in part of a composite fiber reinforced polymer resin matrix, comprising; 
 constructing the container as an assembly of three nested parts, such that circumferential hoop stresses are developed in the winding direction of the broadgoods associated with each part's geometry; and    applying a deformation to each of the three nested parts, characterized by an inward displacement applied to the middle of each of the four side walls so as to make each diagonal dimension of the part smaller than the measured diagonal in the original un-deformed container wall such as to increase the induced compressive residual stresses during construction of the container.    
   
   
       5 . The method of  claim 4  wherein the application of the deformation is accomplished by one-sided curing of the part, whereby, a high heating rate is applied to one side of the part thickness where the other side of the part thickness is in direct contact with a heat sink.  
   
   
       6 . The method of  claim 5  wherein the heating rate is a thermal heat-up ramp > about 60° F./hr.  
   
   
       7 . The method of  claim 4  further comprising constructing the parts such that one of the first or second of the three parts has at least one opening cut in at least one wall.  
   
   
       8 . A blast resistant container constructed at least in part of a composite fiber reinforced polymer resin matrix, characterized by; construction as an assembly of three nested parts, such that circumferential hoop stresses are developed in the winding direction of the broadgoods associated with each part's geometry; and 
 increased induced compressive residual stresses during construction of the container achieved by applying a deformation to each of the three nested parts, characterized by an inward displacement applied to the middle of each of the four side walls so as to make each diagonal dimension of the part smaller than the measured diagonal in the original un-deformed part.    
   
   
       9 . The container of  claim 8  wherein one of the firstmost inner or secondmost inner of the three parts has at least one opening cut in at least one wall.  
   
   
       10 . The container of  claim 9  wherein the opening is closed by installing the outermost third part, and in the event of a blast the expansion of the inner parts to the outer parts seal the opening with a gasket.  
   
   
       11 . The container of  claim 9  wherein the outermost third part has an opening hole which overlaps at least one opening in an at least one inner part, wherein the third part opening is sealed by a blast resistant accordion door of composite construction.  
   
   
       12 . The container of  claim 8  wherein the wall thickness, t, of each wall of the nested parts is determined by: 
 σ=pL/4t, where p is over pressure due to blast, L is the length of the wall and σ is the membrane stress developed in the wall as a result of the overpressure.    
   
   
       13 . A blast resistant accordion door of composite construction for sealing an opening in a blast resistant composite container wall; comprising, 
 piano type hinges where the loops of the hinges constitute cured reinforcing fibers which are the result of folding sidewall fabric back over a Teflon shaft or rod prior to infusion and resin curing, such that the Teflon rod prevents resin from sticking to the shaft thereby allowing the shaft to be extracted after the container shell is fully cured,    lightweight high density polyethylene (HDPE) track positioned along the top and bottom horizontal edges of the door opening, hinge shafts made from continuous S-2 Glass filaments infused with epoxy resin to make a unidirectional reinforced S-2 Glass rod; and,    a high strength lightweight shaft to secure the door inserted into the mating hinges where the left and right sides of the accordion doors meet at the center of the door opening, wherein all tensile circumferential stresses developed by an explosive detonation in the container are transmitted through the door hinges and door panels when the door is closed and secured.    
   
   
       14 . The door of  claim 10  wherein the hinges are co-cured during the fabrication of door panels.  
   
   
       15 . A blast resistant container constructed at least in part of a composite fiber reinforced polymer resin matrix, characterized by; 
 construction as an assembly of three nested parts, such that circumferential hoop stresses are developed in the winding direction of the broadgoods associated with each part's geometry; and,    the wall thickness, t, of each wall of the nested parts is determined by:    σ=pL/4t, where p is over pressure due to a blast, L is the length of the wall and σ is the membrane stress developed in the wall as a result of the overpressure.