Aerospace Engineering Copyright (c) 2013 California Polytechnic State University All rights reserved. http://digitalcommons.calpoly.edu/aerosp Recent documents in Aerospace Engineering en-us Thu, 18 Apr 2013 01:33:03 PDT 3600 SMORE Revision: Ignition and User Interface http://digitalcommons.calpoly.edu/aerosp/105 http://digitalcommons.calpoly.edu/aerosp/105 Tue, 16 Apr 2013 10:37:34 PDT The Static Methanol Oxygen Rocket Engine (SMORE) has undergone several revisions since its inception. This latest revision aimed to increase startup reliability and user safety in the operation of the rocket. The implementation of maintenance procedures, safeguards in the ignition system, as well as construction of a new control box and redesign of the igniter itself have accomplished these goals while keeping costs down and without modifying the current rocket setup. Startup reliability has increased drastically, so long as all other rocket setup procedures are followed properly. 250 subsequent firings of the rocket have proven an igniter reliability of more than 90%. All parts replaced and manufactured in this report have been well documented to ensure ease of maintenance in the future.

]]> Arash Mehrparvar The Architecture Selection, Design, and Discharge Modeling of a Passive Compensation, Iron-Core, Two-Phase, Permanent Magnet Compulsator to Power a Small Railgun Platform http://digitalcommons.calpoly.edu/aerosp/104 http://digitalcommons.calpoly.edu/aerosp/104 Wed, 06 Feb 2013 08:24:37 PST The goal of this project was to design and build a compensated pulsed alternator, or compulsator, to power the Cal Poly Electromagnetic Railgun Mark 1.1. This project examines the feasibility of implementing mechanical pulsed power supplies for repeatable use with a railgun load for orbital debris hypervelocity testing. The final system architecture chosen was a passively compensated, iron-core, 2-phase, permanent magnet compulsator. The Cal Poly Compulsator will be capable of storing 45 kJ of mechanical energy with a peak operating speed of 5,000 rpm at 190 V. Theoretical calculations resulted in the following predicted electrical performance values: a peak output current discharge of 33 kA, peak output power of 3.3 MW, and a pulse width of 4.3 ms. These values result in moving a 1 g projectile to a final velocity of 410 m/s. Experimental testing and comparison will occur once the system has been assembled. The architecture selection process, description of the mathematical modeling of the system, the mechanical design, and some of the manufacturing processes undertaken during this project are included in the discussion. This paper serves as a compilation of introductory information to assist individuals who are just starting their research into compulsators.

]]> Collin MacGregor Thermal Vacuum integration for Cal Poly's Space Environments Laboratory http://digitalcommons.calpoly.edu/aerosp/103 http://digitalcommons.calpoly.edu/aerosp/103 Wed, 06 Feb 2013 08:24:35 PST The purpose of the senior project is to construct a thermal vacuum by utilizing a preexisting vacuum chamber in the Space Environments Lab, and a donated Advanced Thermal Sciences (ATS) chiller. While a thermal vacuum is already available on campus, building one for the Space Environments Lab would grant undergraduates access to the equipment, allowing a much better understanding of testing methods and procedures in use by the aerospace industry. This paper explains the design and analysis of the thermal vacuum (T-VAC) project as well as the operation and procedures required for the ATS chiller and fill/drain tank. The thermal vacuum consists of a vacuum chamber, the ATS chiller and fill/drain tank, Galden HT-110 (a heat transfer fluid), a hot/cold plate, and stainless steel tubing. Patran was utilized to analyze the design of the hot/cold plate and was then verified in a complete run of the T-VAC system. Overall, the system performed close to or better than expected, with the plate reaching a temperature as low as -18°C, and over 100°C in a short period of time, though a leak issue does still need to be resolved.

]]> Chelsea Barackman et al. Two-Stage, High-Altitude Rocket with Internal Skeleton Design Entered in Advance Category of 7th ESRA IREC http://digitalcommons.calpoly.edu/aerosp/102 http://digitalcommons.calpoly.edu/aerosp/102 Wed, 06 Feb 2013 08:24:23 PST A high-altitude, two-stage rocket was designed, built, and entered in the advanced category of the 7th Annual Experimental Sounding Rocket Association (ESRA) Intercollegiate Rocketry Engineering Competition (IREC). The rocket, called AJAKS, featured an internal skeleton made of carbon fiber rods, and a combination of plywood, carbon, and aluminum bulkheads. Loads were driven through the internal structure, with an outer skin tube providing an aerodynamic surface. A unique separation device was developed to ensure proper stage separation. The competition required the rocket to carry a 10-lb payload, which was chosen by the team to consist of an IMU and data logging computer for recording the descent profile, a CubeSat test unit, and a digital video recorder. Prior to the competition launch, AJAKS was test launched on May 5th in the Mojave at the Friends of Amateur Rocketry (FAR) launch facility. During the test launch AJAKS suffered a PIRM malfunction and the main parachute did not deploy. Following the test launch, the second stage of the rocket was rebuilt with a stronger payload configuration. The ESRA IREC was held on June 21st to the 24th. AJAKS was launched on the 23rd and during ascent the second stage became unstable and reached an altitude of only 6,000 ft. Both stages suffered damage upon landing.

]]> Samuel S. Bowman et al. Solar Energy Collection Analysis Tool for Conceptual Aircraft Design http://digitalcommons.calpoly.edu/aerosp/101 http://digitalcommons.calpoly.edu/aerosp/101 Wed, 12 Dec 2012 13:02:32 PST As battery energy storage and solar cell technology improve, solar aircraft are increasingly being considered for High Altitude Long Endurance missions. Although solar vehicles may theoretically remain on-station indefinitely using the sun as a power source, their design and feasibility is sensitive to mission planning details as specific as the time history of the vehicle’s deck orientation relative to the sun; the energy available for capture by the on-board solar array is governed by the solar incidence angle, and at certain orientations, the vehicle may cast shadows on itself and further reduce its energy capture capabilities. To quantify these losses, a batch mode program was developed that takes the vehicle geometry and sun orientation, integrates incidence and shadow losses, and outputs an equivalent effective solar array collection area for use in a vehicle and mission analysis environment. In this paper, the need for such a tool is identified, tool methodology is described, and example output and validation cases are presented.

]]> Grant Glazebrook Manufacturing Processes in an All-aluminum Airframe http://digitalcommons.calpoly.edu/aerosp/100 http://digitalcommons.calpoly.edu/aerosp/100 Wed, 12 Dec 2012 13:02:31 PST One often overlooked aspect to building an aircraft is the manufacturing process used to put it into production. This may be a major contributor to acquisition cost and requires a large amount of money to implement. Once all the tooling has been purchased, one of the greatest costs is labor. The experience of building an all-aluminum aircraft shows that the production process is one which may be done in many different ways. Minimizing the assembly time is important for aircraft manufacturers and one of the best ways to do that is on the assembly line itself. Specific practices in the manufacturing process can speed up production, and this paper shows some practical examples of that.

]]> Stewart McDougall De-Orbiting Upper Stage Rocket Bodies Using a Deployable High Altitude Drag Sail http://digitalcommons.calpoly.edu/aerosp/99 http://digitalcommons.calpoly.edu/aerosp/99 Wed, 12 Dec 2012 13:02:29 PST This report examines the effectiveness of a drag sail to de-orbit upper stage rocket bodies. Many other perturbations contribute to the de-orbiting of these rocket bodies, and these perturbations will also be discussed briefly. This paper will show the length of time needed to force the altitudes of various launch vehicle stages with varying drag area sizes to less than 100 km. The upper stage of the Delta IV launch vehicle in an orbit with an altitude of 500 km will naturally de-orbit in 720 days but when equipped with a 20 m2 drag sail, it will de-orbit in just 510 days. For this particular example the 29% reduction in de-orbit time is very significant. Multiple examples will be displayed in this report to demonstrate the effectiveness of such a drag sail.

]]> Robert A. Hawkins Jr. et al. Validation of the Ballistic Limit Equation for Monolithic Aluminum Shielding at Geostationary Orbital Debris Impact Velocity http://digitalcommons.calpoly.edu/aerosp/98 http://digitalcommons.calpoly.edu/aerosp/98 Thu, 29 Nov 2012 13:47:44 PST The Cal Poly Electro Magnetic Rail Gun was used to eject a 0.370 gram, rectangular aluminum projectile towards a 1/16 inch monolithic aluminum plate at a speed of 280 ± 50 m/s. The resulting impact left a large attached spall on the back of the shielding. The impact damage was compared to an industry ballistic limit equation for a spherical aluminum projectile of similar diameter and was shown to have slightly less damage than the expected results.

In addition, an aluminum mesh double bumper shield was fired upon in order to verify its higher protection per aerial density as well as its higher projectile break-up ability. An impact at 459 ± 50 m/s resulted in superior shielding performance over an aluminum monolithic shield of equivalent areal density, based on the ballistic limit equation; however projectile break up did not occur. A minimum mass savings of 23% was realized using the mesh double bumper shield. Furthermore, when an additional aluminum bumper was placed in front of the mesh bumper, even greater ballistic protection was achieved with a minimum mass savings of over 65%.

]]> Brandon Holladay Three-Axis Stabilized Earth Orbiting Spacecraft Simulator http://digitalcommons.calpoly.edu/aerosp/97 http://digitalcommons.calpoly.edu/aerosp/97 Thu, 29 Nov 2012 13:47:43 PST This report details the method and results of the program created for simulating an Earth orbiting spacecraft with control actuators and orbital perturbations. The control actuators modeled are reaction thrusters, reaction/momentum wheels, and control moment gyros (CMG). The perturbations modeled were gravity gradient, electromagnetic torques, solar radiation pressure, gravity gradients, third-body effects, Earth oblateness and atmospheric drag. This simulation allows for satellite control in all 6 degrees of freedom for any Earth orbiting spacecraft. Assumptions include rigid body dynamics, no sensor noise, constant spacecraft cross-sectional area, constant coefficient of drag and reflectivity, ignoring the effects due to the moon, moment of inertia doesn’t change with a change in mass, and reaction thrusters only produce torque. The results from test trials showed reasonable numbers and system behavior.

]]> Alan F. Ma et al. Effect of Multifunctional Material on the Mechanical Behavior of Composite Structure Using Finite Element Analysis http://digitalcommons.calpoly.edu/aerosp/96 http://digitalcommons.calpoly.edu/aerosp/96 Tue, 13 Nov 2012 16:04:11 PST Nicholas A. Romonoski Performance Effects of Damage Arrestment Devices on Sandwich Composite Beams under Monotonic Loading http://digitalcommons.calpoly.edu/aerosp/95 http://digitalcommons.calpoly.edu/aerosp/95 Tue, 25 Sep 2012 15:33:26 PDT Face-core delamination has become a subject matter in the Aerospace industry, as it can lead to early failure. In this study, sandwich composite beams are tested initially with no delamination to obtain the ultimate strength. A second case of delamination in the center of the beam in initialized to verify a decrease in ultimate strength. This experiment investigates the performance effects of the addition of Damage Arrestment Devices (DADs), in composite sandwich beams. The performance criterion is measured by strength in flexural loading test. The objective of this project is to verify an increase in the strength and performance with the addition of DADs in a sandwich composite. Theoretical and experimental results confirmed that adding damage arrestment devices into the sandwich composite material increases the loading capability of the structure.

]]> Yvette Vanessa Wood A Study on Organic Epoxy and Hemp Composite Plates with an Emphasis on Mechanical and Finite Element Analysis http://digitalcommons.calpoly.edu/aerosp/94 http://digitalcommons.calpoly.edu/aerosp/94 Tue, 25 Sep 2012 14:58:20 PDT Several vibration and tensile tests were conducted for four natural fiber hemp composites in order to observe its behavior and acquire the material properties of hemp. Two plates were made on the Cal Poly press table, while the other two plates were made on the Cal Poly vacuum table. All four plates are made of 100% hemp under three different types of weave. The first plate is called CTPT-12, has a thickness of 0.053 inches, and was made on the press table. The second plate is called CTL4 with a thickness of 0.152 inches and made on the press table. The third plate is called HL-10 with a thickness of 0.2145 inches, and made on the vacuum table. The fourth plate is called CTPT-12 with a thickness of 0.264 inches and made on the vacuum table. A second portion of the project was performed to further study the behavior of hemp composites. Several hemp plates with dimensions of 1.5 inch by 6 inch were made. These plates were manufactured in the vacuum table with four layers of CTPT-12 material and a 1 inch by 1.5 inch delamination. The results indicated a maximum stress of 118280 psi and a maximum displacement of 2 inches from end to end. Each plate was made with organic epoxy under a curing cycle that lasted about a day at a temperature of 150° F. Each plate had a different material property due to its different weave and manufacturing process.The plate that resisted the highest force and the highest Young’s Modulus was the fourth plate with 704 lbf and 937 ksi, respectively. Plate 2 resisted the least with a force of 278 lbf and a Young’s Modulus of 554 ksi. Plate 3 had the lowest Young’s Modulus of 513 ksi with a force of 379 lbf. The vibration sweep ranged from 5 Hz to 1000 Hz with varying control amplitude throughout the run. The results indicated that there were significant differences between the four plates. The first plate had the highest natural frequency of 69.93 Hz at a distance of 4 inches from the surface of the aluminum blocks holding the plate for the vibration test. Plate 2 had the lowest frequency of 5 Hz when the accelerometer was placed 8 inches from the surface of the aluminum blocks. The experiment concluded that the experimental values and the finite element analysis had some similar results.

]]> Alma Melendez Development of a Pyrotechnic Shock Simulation Apparatus for Spacecraft Applications http://digitalcommons.calpoly.edu/aerosp/93 http://digitalcommons.calpoly.edu/aerosp/93 Tue, 25 Sep 2012 14:58:14 PDT This report details the research, design, construction, and testing of a pyrotechnic shock simulation apparatus for spacecraft applications. The apparatus was developed to be used in the Space Environments Lab at California Polytechnic State University. It will be used for testing spacecraft components with dimensions up to 24”x12”x12” as well as CubeSats. Additionally, it may be used as an instructional or demonstrational tool in the Aerospace Department’s space environments course. The apparatus functions by way of mechanical impact of an approximately 20 lb stainless steel swinging hammer. Tests were performed to verify the simulator’s functionality. Suggestions for improvement and further progress are also given.

]]> Joseph Binder et al. The Numerical Open-Source Many-Body Simulator (NOMS) http://digitalcommons.calpoly.edu/aerosp/92 http://digitalcommons.calpoly.edu/aerosp/92 Wed, 12 Sep 2012 14:12:54 PDT This paper outlines the setup and creation of an object-oriented N-body simulator as part of a continued project to explore physical phenomenon and human-computer natural interaction technologies. The tools and processes required to build an N-body simulator are also included. Several integrators were evaluated based on their ability to maintain system energy The 2nd order integrator Verlet and 3rd order integrator Hermite algorithms had the greatest accuracy to model large-scale N-body dynamics for their given computation time. Other algorithms required significantly shorter time steps to achieve similar short-term accuracy. At present, NOMS can reasonably simulate 10,000 particles at less than one minute per iteration.

]]> Jason Lloyd Daniel et al. Control Experiment: Model Helicopter http://digitalcommons.calpoly.edu/aerosp/91 http://digitalcommons.calpoly.edu/aerosp/91 Mon, 06 Aug 2012 11:10:40 PDT This report describes the design and analysis of a control experiment to be implemented in the AERO 320 curriculum. The purpose of the experiment is to give the students hands-on experience working with a control system. In addition, the experiment aims to demonstrate the effect a proportional, integral, derivative (PID) controller has on a control system. The system to be controlled is a model helicopter, constrained to vertical motion. The physical system was built using radio controlled (RC) components, off-the-shelf products, and custom designed parts. The system was tested using an RC transmitter and receiver to manually control the height of the model. A Simulink model with PID controller and simplified plant model was developed and analyzed. A Routh-Hurwitz tabulation was conducted to determine the range of controller gains that would stabilize the system. The gains were varied to determine the effect on the step response and Bode diagram for the helicopter model. The results showed that the changing gain values did not affect the phase margin or gain crossover frequency of the system. Future improvements to the physical system and Simulink model are covered in detail at the end of the report with end goal of testing the system closed loop.

]]> Matthew D. Lattanzi Electromagnetic Railgun Safety http://digitalcommons.calpoly.edu/aerosp/90 http://digitalcommons.calpoly.edu/aerosp/90 Mon, 06 Aug 2012 11:10:35 PDT The Cal Poly Electromagnetic Railgun is a system that with the proper precautions can be safely operated. Changes in plugs and boxes insure that the systems cannot be improperly wired, reducing the chances of accidental discharge. By covering exposed wires the system is safe to store as long as the voltage is checked before any maintenance is performed. Updates in procedures remove the possibility of injury to personnel and allow the railgun to be fired repeatedly under similar circumstances. Defined roles for the operators’ decreases confusion and allows people to concentrate on their area during testing. As hardware changes it will be necessary for continued documentation and updating of procedures, as well as continued safety improvements to insure safe and consistent testing.

]]> Sven Ericson Comprehensive Matlab GUI for Determining Barycentric Orbital Trajectories http://digitalcommons.calpoly.edu/aerosp/89 http://digitalcommons.calpoly.edu/aerosp/89 Wed, 18 Jul 2012 16:36:04 PDT When a 3-body gravitational system is modeled using a rotating coordinate frame, interesting applications become apparent. This frame, otherwise known as a barycentric coordinate system, rotates about the system’s center of mass. Five unique points known as Lagrange points rotate with the system and have numerous applications for spacecraft operations. The goal of the Matlab GUI was to allow easy manipulation of trajectories in a barycentric coordinate system to achieve one of two end goals: a free-return trajectory or a Lagrange point rendezvous. Through graphical user input and an iterative solver, the GUI is capable of calculating and optimizing both of these trajectory types for all of our solar system’s planets. Its inputs are inertial state vectors, a date and time, and the number of propagation days. The user can then graphically manipulate the resulting trajectories by increasing the spacecraft velocity and propagation start time. It outputs the resulting ΔV vectors and magnitudes as well as a graphical representation of the desired orbital path.

]]> Steve Katzman The Study of Natural Composite I-Beam in a Three Point Bending Test http://digitalcommons.calpoly.edu/aerosp/88 http://digitalcommons.calpoly.edu/aerosp/88 Mon, 09 Jul 2012 10:18:14 PDT The objective of this experiment is to conduct a series of unidirectional tensile test on several samples of natural occurring plant fibers. Among the materials tested, hemp has proven to be the most promising candidate as the base material in creating an all-natural composite I-Beam. This I-Beam will be entered into the annual SAMPE 2012 competition to compete against other schools and universities nationwide. These I-Beams will undergo a three point bending test, and must withstand the greatest load whilst remaining in the parameters set by SAMPE. This I-Beam will go on to take third place internationally. In addition, the properties of hemp composites will be further investigated by creating the same I-Beam, but introducing a small fracture to the underside in order to observe how the composite interacts in the presence of fracture.

]]> Abdel Shabbar Degradation of Solar Cells Due to Arcing in a Vacuum Chamber http://digitalcommons.calpoly.edu/aerosp/87 http://digitalcommons.calpoly.edu/aerosp/87 Wed, 27 Jun 2012 08:39:03 PDT This report summarizes the senior project entitled Degradation of Solar Cells Due to Arcing in a Vacuum Chamber. The goal of this experiment was to show electrical and physical degradation of silicon solar cells in a vacuum chamber. The cells were characterized and then placed in a vacuum chamber. Under vacuum, a potential was created to induce arcing to the cell. The cell was characterized again after arcing to determine the change in efficiency. This document details the process for designing the circuit to create the arcing, and the different setups used to degrade the cells electrically and physically. It also describes the final setups to be used in the lab write-up for the Aerospace Engineering Department’s Spacecraft Environment Laboratory.

]]> Christina Gonzalez Assembly of a Passive Slat System for a CH-701 Kit Aircraft http://digitalcommons.calpoly.edu/aerosp/86 http://digitalcommons.calpoly.edu/aerosp/86 Wed, 27 Jun 2012 08:38:56 PDT Jordan Coenen et al.