Multidisciplinary design optimization of an expendable launch vehicle

Abstract

This paper describes an effort to optimize the design of an expendable launch vehicle (ELV) to low-Earth orbit, consisting of multiple stages with the goal of minimizing total vehicle weight and ultimately vehicle cost. The disciplines of weight & sizing, propulsion characteristics, aerodynamics and flight dynamics have been integrated to produce a system model of the entire vehicle. One multilevel multidisciplinary optimization techniques -Collaborative -is applied to the design of a launch vehicle. The results inclusive designed launch vehicle data has been validated by existing launch vehicle data. Keywords-Launch vehicle (LV), System design, Optimization, MDO, Design framework. I. NOMENCLATURE R = Earth radius E ω = Earth rotational velocity φ = Launch point latitude Hp = Orbit perigee altitude Ha = Orbit apogee altitude i = Orbit inclination ei μ = proportion of empty mass to total mass for (i)th stage ei M = empty mass for (i)th stage i M 0 = total mass for (i)th stage i n = load factor for (i)th stage MDO = multidisciplinary design optimization a, b, c = coefficient of mass & energy PL μ = proportion of payload mass to total mass CD = coefficient of drag D L = proportion of length to diameter N = number of stages ELV = Expendable Launch Vehicle LV = Launch Vehicle FPI = Fixed Point Iteration BLISS = Bi-level integrated system synthesis CO = Collaborative Optimization CAs = contributing analyses

A New Approach to Multidisciplinary Design Optimization of Solid Propulsion System Including Heat Transfer and Ablative Cooling

“…Over the years, 2 main design approaches have persisted. First, designers try several alternate designs and use the fi xed-point iteration (FPI) process to converge them (Hosseini et al 2011). A global criterion is used to choose the best design, but, because no global optimization takes place, there is no guarantee that the global optimum is reached.…”

“…Th is is the conventional method. Alternatively, multidisciplinary design optimization (MDO) technique simultaneously optimizes every discipline and fi nds a global optimum solution (Hosseini et al 2011). Unfortunately, decoupling of disciplines has optimization penalty and low methods and heuristic methods by combining the speed of local optimization with the robustness of global optimization.…”