This paper discusses the development of an Earth Entry Vehicle (EEV) concept and the novel methodology proposed to evaluate its structural dynamic response during launch and reentry. The upcoming NASA Mars Sample Return Mission (MSR) planned for launch in the 2020s requires a simple and reliable method to return Martian samples back to Earth for analysis. The EEV is the proposed solution to this MSR requirement. The EEV concept is also 'multi-mission' in that the basic structural design can be be tailored for other missions beyond MSR with different payload and mission parameters but with the same goal of safely transfering payload from space to a planet's surface. During launch and reentry an EEV may experience large structural loads from many different sources. In an effort to decrease development time and cost, a fully parametric and automated finite element analysis methodology was developed. In contrast to the typical method of building models using a preprocessor GUI, the developed methodology builds EEV models using a coding technique. This technique allows for the quick modification of nearly all aspects of the model including: geometric dimensions, material properties, load and boundary conditions, mesh properties, and analysis controls. Furthermore once the model parameters are defined, all required analyses can be completed automatically. Given the proper computational resources, the developed methodology can be used to rapidly generate data for a wide array of potential EEV configurations. A range of analyses including quasi-static inertial, structure-borne vibration frequency response, random acoustic, and aeroelastic analyses were conducted. To demonstrate the parametric capabilities of the model, key geometric dimensions were varied and then all analyses were executed. The results for each set of analyses are presented and compared. In this paper it is demonstrated that the developed structural analysis methodolody has great potential in facilitating a myriad of future cost-effective space and planetary exploration missions.
NomenclatureEEV = Earth entry vehicle MSR = Mars sample return OS = Orbiting sphere IS = Impact sphere TPS = Thermal protection system SDM = Structural dynamics model PCL = Patran command language PSD = Power spectral density RMS = Root mean squared BC = Boundary condition 1 PhD Student, CRASH Lab, Virginia Tech, Blacksburg, VA, 24061-0238, AIAA Student Member. 2 Associate Professor, CRASH Lab, Virginia Tech, Blacksburg, VA 24061-0238, AIAA Associate Fellow. 3 Senior Research Engineer, Vehicle Analysis Branch, MS 451, AIAA Associate Fellow. 4 Senior Research Engineer, Structural and Thermal Systems Branch, MS 431. Downloaded by PRINCETON UNIVERSITY on July 29, 2015 | http://arc.aiaa.org |