Hybrid metal composite structures, rocket motors and multi-stage rocket motor assemblies including hybrid metal composite structures, and related methods

Abstract

A hybrid metal composite (HMC) structure comprises a first tier comprising a first fiber composite material structure, a second tier longitudinally adjacent the first tier and comprising a first metallic structure and a second fiber composite material structure laterally adjacent the first metallic structure, a third tier longitudinally adjacent the second tier and comprising a third fiber composite material structure, and a fourth tier longitudinally adjacent the third tier and comprising a second metallic structure and a fourth fiber composite material structure laterally adjacent the second metallic structure. At least one lateral end of the second metallic structure is laterally offset from at least one lateral end of the first metallic structure most proximate thereto. Methods of forming an HMC structure, and related rocket motors and multi-stage rocket motor assemblies are also disclosed.

What is claimed is: 
     
         1 . An HMC structure, comprising:
 a first tier comprising a first fiber composite material structure;   a second tier longitudinally adjacent the first tier and comprising a first metallic structure and a second fiber composite material structure laterally adjacent the first metallic structure;   a third tier longitudinally adjacent the second tier and comprising a third fiber composite material structure; and   a fourth tier longitudinally adjacent the third tier and comprising a second metallic structure and a fourth fiber composite material structure laterally adjacent the second metallic structure, at least one lateral end of the second metallic structure laterally offset from at least one lateral end of the first metallic structure most proximate thereto.   
     
     
         2 . The HMC structure of  claim 1 , wherein:
 first lateral ends of the first metallic structure and the second metallic structure are laterally offset from one another; and   second lateral ends of the first metallic structure and the second metallic structure are substantially aligned with one another.   
     
     
         3 . The HMC structure of  claim 1 , wherein:
 first lateral ends of the first metallic structure and the second metallic structure are laterally offset from one another; and   second lateral ends of the first metallic structure and the second metallic structure are also laterally offset from one another.   
     
     
         4 . The HMC structure of  claim 1 , wherein lateral centers of the first metallic structure and the second metallic structure are substantially aligned with one another. 
     
     
         5 . The HMC structure of  claim 1 , wherein lateral centers of the first metallic structure and the second metallic structure are laterally offset from one another. 
     
     
         6 . The HMC structure of  claim 5 , wherein the first metallic structure exhibits substantially the same width as the second metallic structure. 
     
     
         7 . The HMC structure of  claim 5 , wherein the first metallic structure exhibits a different width than the second metallic structure. 
     
     
         8 . The HMC structure of  claim 1 , wherein the at least one lateral end of the second metallic structure is laterally offset from the at least one lateral end of the first metallic structure most proximate thereto by a distance greater than or equal to about ten times a thickness of the second metallic structure. 
     
     
         9 . The HMC structure of  claim 1 , further comprising:
 a fifth tier longitudinally adjacent the fourth tier and comprising a fifth fiber composite material structure; and   a sixth tier longitudinally adjacent the fifth tier and comprising a third metallic structure and a sixth fiber composite material structure laterally adjacent the third metallic structure, at least one lateral end of the third metallic structure laterally offset from one or more of the at least one lateral end of the second metallic structure and the at least one lateral end of the first metallic structure.   
     
     
         10 . The HMC structure of  claim 9 , wherein:
 first lateral ends of the first metallic structure, the second metallic structure, and the third metallic structure are laterally offset from one another; and   second lateral ends of the first metallic structure, the second metallic structure, and the third metallic structures are substantially aligned with one another.   
     
     
         11 . The HMC structure of  claim 9 , wherein the at least one lateral end of the third metallic structure is substantially aligned with the at least one lateral end of the first metallic structure. 
     
     
         12 . The HMC structure of  claim 9 , wherein the at least one lateral end of the third metallic structure is substantially aligned with the at least one lateral end of the second metallic structure. 
     
     
         13 . The HMC structure of  claim 9 , wherein lateral centers of the first metallic structure, the second metallic structure, and the third metallic structure are substantially laterally aligned with one another. 
     
     
         14 . The HMC structure of  claim 9 , wherein a lateral center of the third metallic structure is laterally offset from a lateral center of one or more of the first metallic structure and the second metallic structure. 
     
     
         15 . The HMC structure of  claim 9 , wherein each of the first metallic structure, the second metallic structure, and the third metallic structure exhibits a different width than each other of the first metallic structure, the second metallic structure, and the third metallic structure. 
     
     
         16 . The HMC structure of  claim 9 , wherein the third metallic structure exhibits substantially the same width as one or more of the first metallic structure and the second metallic structure. 
     
     
         17 . The HMC structure of  claim 1 , wherein:
 a thickness of the second fiber composite material structure is an integer multiple of a thickness of the first metallic structure; and   a thickness of the fourth fiber composite material structure is an integer multiple of a thickness of the second metallic structure.   
     
     
         18 . A method of forming an HMC structure, comprising:
 forming a first tier comprising a first fiber composite material structure over a substrate;   forming a second tier comprising a first metallic structure and a second fiber composite material structure over the first tier;   forming a third tier comprising a third fiber composite material structure over the second tier;   forming a fourth tier comprising a second metallic structure and a fourth fiber composite material structure over the third tier, at least one lateral end of the second metallic structure laterally offset from at least one lateral end of the first metallic structure most proximate thereto;   forming a fifth tier comprising a fifth fiber composite material structure over the fourth tier; and   subjecting at least the first tier, the second tier, the third tier, the fourth tier, and the fifth tier to at least one curing process.   
     
     
         19 . The method of  claim 18 , wherein forming a fourth tier comprises positioning the second metallic structure relative to the first metallic structure such that first lateral ends of the first metallic structure and the second metallic structure are laterally offset from one another and second lateral ends of the first metallic structure and the second metallic structure are substantially aligned with one another. 
     
     
         20 . The method of  claim 19 , further comprising trimming portions of the first fiber composite material structure, the second fiber composite material structure, the third fiber composite material structure, the fourth fiber composite material structure, and the fifth fiber composite material structure laterally proximate the second lateral ends of the first metallic structure and the second metallic structure without trimming portions of the first metallic structure and the second metallic structure. 
     
     
         21 . The method of  claim 18 , further comprising trimming portions of the first fiber composite material structure, the first metallic structure, the second fiber composite material structure, the third fiber composite material structure, the second metallic structure, the fourth fiber composite material structure, and the fifth fiber composite material structure to substantially laterally align at least one other lateral end of the first metallic structure with at least one other lateral end of the second metallic structure. 
     
     
         22 . A rocket motor, comprising:
 a casing comprising an HMC structure comprising:
 primary tiers comprising fiber composite material structures; and 
 secondary tiers longitudinally adjacent one or more of the primary tiers and comprising metallic structures and additional fiber composite material structures laterally adjacent the metallic structures, one or more lateral ends of at least one of the metallic structures laterally offset from one or more corresponding lateral ends of at least other of the metallic structures longitudinally neighboring the at least one of the metallic structures; 
   a propellant structure within the casing; and   a nozzle assembly connected to an aft end of the casing.   
     
     
         23 . The rocket motor of  claim 22 , wherein the casing further comprises an additional HMC structure laterally adjacent and connected to the HMC structure, the additional HMC structure comprising:
 additional primary tiers comprising other fiber composite material structures; and   additional secondary tiers longitudinally adjacent one or more of the additional primary tiers and comprising additional metallic structures and other additional fiber composite material structures laterally adjacent the additional metallic structures, one or more lateral ends of at least one of the additional metallic structures laterally offset from one or more corresponding lateral ends of at least one other of the additional metallic structures longitudinally neighboring the at least one of the additional metallic structures.   
     
     
         24 . The rocket motor of  claim 23 , wherein the HMC structure is connected to the additional HMC structure through at least one fastener assembly comprising:
 an outer joining structure overlying portions of the HMC structure and the additional HMC structure;   an inner joining structure underlying the portions of the HMC structure and the additional HMC structure;   elongate structures longitudinally extending through the outer joining structure, the portions of the HMC structure and the additional HMC structure, and the inner joining structure; and   capping structures connected to opposing ends of each of the elongate structures.   
     
     
         25 . The rocket motor of  claim 24 , wherein a portion of the elongate structures of the at least one fastener assembly longitudinally extend through at least some of the metallic structures of the HMC structure, and wherein another portion of the elongate structures of the at least one fastener assembly longitudinally extend through at least some of the additional metallic structures of the additional HMC structure. 
     
     
         26 . A multi-stage rocket motor assembly, comprising:
 an outer housing having a closed forward end and an open aft end, and comprising at least one HMC structure comprising:
 tiers comprising fiber composite material structures; and 
 additional tiers longitudinally adjacent one or more of the tiers and comprising metallic structures and additional fiber composite material structures laterally adjacent the metallic structures, one or more lateral ends of at least one of the metallic structures laterally offset from one or more corresponding lateral ends of at least one other of the metallic structures longitudinally neighboring the at least one of the metallic structures; and 
   stages provided in an end-to-end relationship with one another within the outer housing, each of the stages comprising:
 a casing; 
 a propellant structure within the casing; and 
 a nozzle assembly connected to an aft end of the casing.