SAWE Technical Papers

@inproceedings{3791,

title = {3791. Reverse Engineering the Mass Properties of a Civil Aviation Aircraft},

author = {Darrin McCloud},

url = {https://www.sawe.org/product/paper-3791},

year  = {2023},

date = {2023-05-20},

urldate = {2023-05-20},

booktitle = {82nd Annual Conference, Cocoa Beach, Florida},

pages = {22},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Cocoa Beach, Florida},

abstract = {In Mid-2017 I started my first project taking a certified civilian aircraft and turning it into a special mission aircraft while working in a small consultant company. This was not a small project, it involved numerous airframes and significant aerodynamic and secondary structural modifications in addition to a completely new cabin layout with equipment installed throughout the cabin. This project was being run and integrated by a large, well known US company, but they subcontracted out the aircraft portion, including structural modifications and certification to a smaller Modification Center company. Due to contract issues, the Original Manufacturer (OEM) would not be supporting any of the modification efforts. My company, which specializes in static and dynamic loads certification, was subcontracted for Loads certification and would need to have complete aerodynamic and mass properties data for both the standard and modified aircraft to be able to show compliance with all the applicable Federal Airworthiness Regulations (FARs). As the sole mass properties engineer on the program, I would be entirely responsible for creating detailed mass properties for an aircraft while only using the paperwork that comes with a customer aircraft and any public information available on the internet or in print. This paper will document the system that was devised, and has continued to be used on numerous other projects, where detailed mass properties data is needed for customer certification issues without the benefit of any OEM engineering reports.},

keywords = {Aircraft - Commercial},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3792,

title = {3792. Road Accident Reconstruction: The Role of the Inertia Properties},

author = {Massimiliano Gobbi and Gianpiero Mastinu and Giorgio Previati},

url = {https://www.sawe.org/product/paper-3792},

year  = {2023},

date = {2023-05-20},

urldate = {2023-05-20},

booktitle = {82nd Annual Conference, Cocoa Beach, Florida},

pages = {15},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Cocoa Beach, Florida},

abstract = {The reconstruction of car accidents is a critical step in understanding the causes of an accident and, in case, for attributing responsibilities. Therefore, the reconstruction must be realized by considering all of the possible sources of error and misrepresentation. Since such activity relies on dynamic models of the colliding vehicles, mass properties (mass, centre of gravity location, inertia tensor) play a crucial role. 

The present papers aims to quantify the requirements in the knowledge of the inertia properties for a proper reconstruction of car accidents. The analysis is performed with reference to the case of two colliding vehicles. After a detailed description of the model employed for the reconstruction, dynamic simulation are utilized to assess the required accuracy, with particular reference to the effects of the uncertainty in mass, longitudinal location of the centre of gravity and yaw moment of inertia. It turns out that even relatively small errors in the definition of such parameters can lead to large errors in the reconstruction of the state of the colliding vehicles before the accident. Also, the variation in the inertia properties of the vehicles due to the crash is investigated. Engineers involved in car accident reconstruction should be aware of the importance of correctly estimate the inertia properties of vehicle, both before and after the accident, to obtain a correct estimation of the actual dynamic of the accident.},

keywords = {Ground Vehicles},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3793,

title = {3793. Effects of Mass and Pitch Moment of Inertia on Vehicle Suspension Design With Race Car Example},

author = {Pietro Stabile and Federico Ballo and Giorgio Previati},

url = {https://www.sawe.org/product/paper-3793},

year  = {2023},

date = {2023-05-20},

urldate = {2023-05-20},

booktitle = {82nd Annual Conference, Cocoa Beach, Florida},

pages = {11},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Cocoa Beach, Florida},

abstract = {The present paper addresses the topic of studying the influence of the main vehicle inertia parameters on the suspension design. A simple four degrees-of-freedom half-car model is used to describe the dynamic behaviour of vehicles running on randomly profiled roads. The response of the system is analysed by evaluating three performance indexes, namely driver discomfort, road holding and working space, referring to the standard deviations of driver seat vertical acceleration, force at ground and relative displacement between wheels, respectively. The effect of varying wheel mass, vehicle mass, centre of gravity longitudinal location and pitch moment of inertia on the three performance indexes is investigated. The proposed approach is applied to the design of the suspension system of a vehicle conceived for efficiency-based competitions. Based on these results, considerations on the best location for battery pack and ballast are drawn.},

keywords = {Ground Vehicles, Student Papers},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3794,

title = {3794. The Mass Properties Function during The Aircraft Interior Outfitting},

author = {Luis A. Lopez},

url = {https://www.sawe.org/product/paper-3794},

year  = {2023},

date = {2023-05-20},

urldate = {2023-05-20},

booktitle = {82nd Annual Conference, Cocoa Beach, Florida},

pages = {20},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Cocoa Beach, Florida},

abstract = {Outfitting is defined as the introduction and physical addition of custom furnishings, cabin entertainment systems, cabin insulation, acoustics materials, seats, and others to a “green aircraft”, a plane without interiors or other components at a completion center facility per customer definition. 

By its nature, outfitting will vary from one aircraft to another, depending on number of seats, degree of function or luxury elements and location of interior components. Mass properties are the physical properties of an object that describe all its mass, center of gravity, and moment of inertia. These properties are impacted when outfitting interiors are introduced in the aircraft as they are typically the last step of the manufacturing build on an aircraft, however they will influence and define the final performance and handling of an aircraft. 

The intention of this paper is to explore the aircraft interiors outfitting activity as it relates to the Completions Mass Properties Engineer function and its effects at the final build. 

We briefly explore areas that are related to the completions function from the mass properties perspective. We will use simple terms to highlight the important responsibility of the Mass Properties Engineer in the outfitting final phase’s role on a typical OEM (Original Equipment Manufacturer). A discipline that is not well understood by colleagues and the public in general due to the specialized nature of the work.},

keywords = {Aircraft},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3795,

title = {3795. Aerostructural Weight Estimation for a Transonic Truss-Braced Wing Using the Higher-Fidelity Conceptual Design and Structural Optimization Tool},

author = {Zachary Windous and Jesse R. Quinlan},

url = {https://www.sawe.org/product/paper-3795},

year  = {2023},

date = {2023-05-20},

urldate = {2023-05-20},

booktitle = {82nd Annual Conference, Cocoa Beach, Florida},

pages = {11},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Cocoa Beach, Florida},

abstract = {Continued development and enhancements of the Higher-fidelity Conceptual Design and structural optimization (HCDstruct) tool have been driven largely by advanced aircraft concepts of interest to NASA. While previous versions of HCDstruct were limited to hybrid wing body (HWB) and generalized tube and wing (TW) aircraft concepts, the latest version of HCDstruct supports the analysis of Truss-Braced Wing (TBW) aircraft concepts, enabling users to model both high and low wing configurations as well as strut and jury geometries parametrically. Additionally, new methods for modeling advanced composite materials within HCDstruct have been implemented. These recent tool enhancements were demonstrated for an independent assessment of the NASA/Boeing SUGAR Phase VI Mach 0.8 Transonic Truss-Braced Wing (TTBW) concept.},

keywords = {Aircraft},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3738,

title = {3738. Aft Perpendicular... An Afterthought?},

author = {Scott Daley and Rob Dvorak and Matt Marburger},

url = {https://www.sawe.org/product/paper-3738},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {12},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {How do you define the length of a ship? What is the definition of aft perpendicular? From the Principles of Naval Architecture (PNA), the definition for the location of the aft perpendicular “is at the aft side of the rudder post, centerline of the rudder stock, or at the intersection of the design waterline with the aft end of the vessel.” However, for U.S. submarines, the location of the aft perpendicular has not always followed PNA’s definition. The location for a submarine’s aft perpendicular has been at the end of the thrust device or at an outdated feature. This paper will examine the technical details, design maturity and timeline, and implications of how the aft perpendicular on a submarine is defined.},

keywords = {Marine},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3745,

title = {3745. Weight Management for Onshore Modular Construction},

author = {Robert J. Hundl},

url = {https://www.sawe.org/product/paper-3745},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {38},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {This weight management paper will become a chapter in a larger document on Onshore modular construction that is being put together by the Process Industries Practices (PIP) Civil, Structures, and Architectural (CSA) Task Team #3 committee. This committee is composed of various engineering construction companies, logistics companies, and owner operator companies. This weight management chapter has been largely authored by myself with inputs and discussions with various PIP committee members and Fluor colleagues. (see the Acknowledgement section at the end of the paper for a full listing of the committee membership and Fluor colleagues) 

Weight Management is a critical aspect of On-Shore Modular Construction. The purpose of this document is to provide guidance on weight management activities as related to various types of on- shore modular projects. This type of construction requires that the modules be transported from the fabrication yard to the project site. The fabrication yard may be located relatively close to the project site requiring only land transportation or it may be located very distant requiring land and ocean transportation.},

keywords = {35. Weight Engineering - Offshore},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3761,

title = {3761. Estimating Mass Moments of Inertia – A Quick Check Method},

author = {Damian P. Yañez},

url = {https://www.sawe.org/product/paper-3761},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {14},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {Mass Moments of Inertia (MOI) are important and often critical components of the mass properties of a vehicle, but many Mass Properties Engineers tend to focus only on weight and center of gravity (CG), and have limited exposure to these other, rotational properties. In this paper, I present a brief overview of MOI, why they are important, and a method for quickly estimating the MOI of a part, subassembly, or assembly. This method is particularly useful when reviewing CAD calculations or a supplier’s mass properties reports in which you don’t have visibility into the details to ensure that the results are reasonable. You can also use this technique to make a quick MOI estimate for trade studies. While there are some limitations to this method which are described in this paper, this technique will get you in the ballpark and increase your confidence that the rotational properties of your vehicle are properly represented.},

keywords = {05. Inertia Calculations, 25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3763,

title = {3763. MauSPAF: Design of an Open-Source Mass Properties Management Framework},

author = {M. Nuño and K. Schröder},

url = {https://www.sawe.org/product/paper-3763},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {18},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {In this paper, an open-source mass properties calculation and management created using Python 3 is presented. The program implements uncertainty calculations using Monte Carlo simulations, mass properties calculations and basic tree structures. It also includes a library with aircraft mass estimation and calculation functions for simple geometrical shapes. To argument the design decisions, a thorough review of available literature about mass calculation tools is performed.},

keywords = {12. Weight Engineering - Computer Applications, Student Papers},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3764,

title = {3764. Technical Authority: What, Why, and How},

author = {David Tellet and Christine Wujick},

url = {https://www.sawe.org/product/paper-3764},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {26},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {Technical authority is a concept where the engineering management hier- archy is separate from the program management hierarchy. The intent of this organizational structure is to insulate engineering calculations and decisions from financial and schedule influences so engineering quality can be preserved. This paper looks at the technical authority structure and process within the US Navy acquisition and engineering directorates and discusses why this system was established and how it works (and doesn’t) in real programs. 

The discussion of technical authority focuses on mass properties of a major submarine acquisition program but also includes insight from the other side: the viewpoint of technical authority from the deputy program manager of that program. Together the paper provides insights and examples of why maintain- ing technical authority is important and also how compromises are navigated between good engineering and good program management.},

keywords = {16. Weight Engineering - Organization},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3766,

title = {3766. Mass Properties and Automotive Braking},

author = {Brian Paul Wiegand},

url = {https://www.sawe.org/product/paper-3766},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {63},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {In 1984, for the 43rd Annual International Conference of the SAWE, this author presented Paper Number 1634, “Mass Properties and Automotive Longitudinal Acceleration”. In that paper the effects upon automotive acceleration of varying the relevant mass property parameters were explored by use of a computer simulation. The computer simulation of automotive longitudinal acceleration allowed for the study of each individual parameter because a simulation allows for the decoupling of the parameters in a way that is not possible physically. The principal mass property parameters involved were the vehicle weight and rotating component inertias, collectively known as the “effective mass”, plus the longitudinal and vertical coordinates of the vehicle center of gravity. 

However, just as it is important for a vehicle to be able to accelerate, it is perhaps even more important for a vehicle to be able to decelerate. The same mass properties that were relevant to the matter of automotive acceleration are also relevant to the matter of automotive deceleration, a.k.a. braking, although for the braking case that collective of vehicle translational inertia and rotational component inertias known as the “effective mass” requires somewhat different handling. As was the case with automotive acceleration, automotive braking will be explored by use of a computer simulation whereby the effect of variation of each of the mass property parameters can be studied independently. However, this task is considerably easier as the creation of a braking simulation is a minor effort compared to the creation of an acceleration simulation. 

Rev B - 2023},

keywords = {31. Weight Engineering - Surface Transportation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3767,

title = {3767. Determining Center of Gravity of Irregular-Shaped Bodies via Suspension},

author = {Emma Markovich},

url = {https://www.sawe.org/product/paper-3767},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {23},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {The precise determination of the center of gravity of an aircraft is essential for the balance, stability, and overall safety of flight. Military aircraft often carry additional attachments, such as wing-mounted surveillance equipment, fuel tanks, or weaponry, which alter the weight and balance characteristics of the aircraft. In the application explored in this paper, a novel suspension system for determining the center of gravity of surveillance pods varying in shape and size is developed. This allows for the calculation of the center of gravity of aircraft attachments utilizing a two-point connection - the same attachment method as used on an aircraft. The tool features a hinged testbed that is suspended from a rigid frame by three load sensing devices. Two measurement sets are taken at different inclinations using an inverted three-point weighing method which allows the center of gravity to be calculated in all three dimensions. To recover measurement accuracy lost due to the limitation of inclination angles to less than 20 degrees, a high precision inclinometer is utilized. Based on the specifications of the sensing equipment and extensive Monte Carlo simulation of errors in force measurement, inclination angle, geometric dimensions, and data sampling, it is expected that the center of gravity can be reliably calculated to within 0.1 inches of the true value. Using the tool, objects ranging from 180 lb to 2000 lb with sizes of up to 12 x 4 x 4 feet can be measured with this accuracy. The modular design of the apparatus, data acquisition methods, and analysis relating to computation of the center of gravity will be presented. Additionally, the paper will discuss error analysis for the measurements, as well as verification and validation methods.},

keywords = {03. Center Of Gravity, Student Papers},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3770,

title = {3770. Mass Management of a High Energy-Efficient Battery Electric Vehicle},

author = {Pietro Stabile and Federico Ballo and Giorgio Previati},

url = {https://www.sawe.org/product/paper-3770},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {15},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {The paper presents a detailed analysis of the mass-induced power demand of an ultra-efficient battery electric vehicle. The vehicle belongs to a special class of lightweight quadricycles, designed for participating to efficiency competitions. The influence of reducing the mass of the entire vehicle and the mass of the wheels on the vehicle energy consumption is assessed. A sensitivity analysis is performed by exploiting a “tank-to- wheel” multi-physics model of the vehicle. The model includes the main vehicle subsystems and the principal sources of power dissipation are modelled. A three-step sensitivity analysis is carried out: firstly, the influence of the mass reduction on the energy saving is analysed for two different race tracks; then, two different driving behaviour on the same track are compared; finally, the potential energy saving due to actual lightweighting interventions performed on the vehicle is computed. In this phase, secondary mass reduction effects (battery downsizing) are included in the simulation. Results are expressed in terms of Energy Reduction Value (ERV), a parameter widely used in the literature to quantify the correlation between mass reduction and energy saving. The vehicle studied in this paper shows an ERV due to vehicle mass reduction ranging from 0.23 to 0.36 kWh/(100 km∙100 kg), while wheel lightweighting leads to an ERV ranging from 1.03 to 1.74 kWh/(100 km∙100 kg).},

keywords = {31. Weight Engineering - Surface Transportation, Student Papers},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3775,

title = {3775. Influence of the Inertia Parameters on a Dynamic Driving Simulator Performances},

author = {Giorgio Previati and Gianpiero Mastinu and Massimiliano Gobbi},

url = {https://www.sawe.org/product/paper-3775},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {14},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {This paper deals with the analysis of the effects of inaccuracies in the knowledge of the inertia properties of a dynamic driving simulator on the performances of its motion control. Dynamic motion simulators aim to reproduce the motion of a vehicle with a high degree of fidelity. The simulators are moved by actuators up to relatively high frequencies. Special algorithms are used to scale the motion of the actual vehicle in order to comply with the travel allowed by the simulator while maintaining the more significant motion characteristics. Such algorithms are fine tuned to reproduce the feeling of each vehicle and suit the expectations of each user. Therefore, the motion controllers of the driving simulators must be able to accomplish the desired motion. Errors in the knowledge of the inertia parameters of the driving simulator can reduce the performances of the controller and increase the tracking error with respect to the desired trajectory.},

keywords = {05. Inertia Calculations, 31. Weight Engineering - Surface Transportation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3776,

title = {3776. Harnessing Historical Company Data for Estimating Weights of Customized Commercial Workboats},

author = {Chandan Deol and Lindsay Johnston},

url = {https://www.sawe.org/product/paper-3776},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {33},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {Robert Allan Ltd., Canada’s most senior Naval Architecture and Marine Engineering firm, specializes in the design of ship-handling tugs and other workboats for a global clientele. On average one to two vessels designed by the firm are launched every week. Almost every vessel is tailored to meet the needs of the client, even if it is based on one of several common hull types. This design flexibility presents a challenge when it comes to estimating weights efficiently and accurately. 

Fortunately, Robert Allan Ltd. can draw on a significant historical database that can be leveraged when estimating vessel weights and centers of gravity for new projects. Over the last six years, the weight engineering team has worked to build a more efficient, rigorous, consistent, and accurate weight estimating procedure for tugs and other commercial workboats while still allowing for client-driven design customization. 

This paper summarizes the process of collecting and utilizing historical data to develop a tool to estimate weights and centers of gravity for a new vessel based on the limited number of inputs available at an early phase of design. It will also address how the development of this tool, which has become a key component of the firm's weight estimating process, has revealed key areas where more specialized tools are required to improve accuracy and efficiency. This has led to Robert Allan Ltd. developing a collection of specialized weight estimating tools and guidelines that address these key areas and cater to the different design phases. Although these tools have evolved to a point where they are widely used throughout the firm, they continue to be modified and upgraded to meet new requirements and include new data.},

keywords = {Marine},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3778,

title = {3778. Mass Properties in Manufacturing},

author = {William Boze},

url = {https://www.sawe.org/product/paper-3778},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {11},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {In a vehicle acquisition program, there is a myriad of groups that use mass properties data and require Mass Properties Engineering support. The user group may vary from product to product. However, almost every product’s Performance, Structures, Loads, Tooling, Manufacturing, Costing, Shipping, and Marketing groups, along with many others, all require accurate mass properties in one form or another (SAWE, 2003). This paper will highlight specifically where mass properties data is utilized by various groups in the planning and construction of a ship, while providing an overview of the manufacturing, construction, assembly, and testing process. While this paper addresses how mass properties data is used in ship production, similar data furnished by the mass properties group is utilized in the construction of aircraft, spacecraft, offshore platforms, and ground transportation vehicles.},

keywords = {17. Weight Engineering - Procedures},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3779,

title = {3779. Determining the Center of Gravity of the Electric No Emissions Low Drag Airframe (NELDA)},

author = {Christl K. Haley},

url = {https://www.sawe.org/product/paper-3779},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {27},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Savannah, Georgia},

abstract = {Although climate change has become an impending issue for all of humanity, it has brought nations together to design and create a variety of systems that leave little to no carbon footprint. The No Emission Low Drag Airframe (NELDA) is a unique electric aircraft design which aims to join this world-wide mission. The author (the airframe design lead) and her senior design team from the University of Colorado Boulder spent the fall semester of 2021 designing this commuter aircraft. NELDA can fly 6 passengers at a cruise altitude of 12,000 ft MSL, at a cruise speed of 150 knots for 1.5 hours with a 30-minute reserve, making this a perfect aircraft for short, direct flights. The characteristics for this aircraft aim to be certified under Federal Aviation Regulation (FAR) 23 to ensure the safety of every passenger. Multiple trade studies were conducted to determine the design choices that make up this innovative aircraft. These studies resulted in an aft-mid-mounted wing, a canard, fixed tricycle landing gear, butterfly doors, and a pusher-propeller powertrain configuration. The specific energy, density, volume, and weight of the electric powertrain were estimated using a 5-year prediction for solid-state batteries. Since these batteries do not exist today, it was very challenging to accurately model and place the power system. The range and endurance of NELDA were used to determine the volume, number, and weight of the batteries. The safety of passengers, size of the batteries, and functionality of each battery were all considered while determining where and how to place the batteries among the other major components of NELDA. Additionally, it was critical to strategically place each of the components to achieve an acceptable static margin of 10%, as well as predictable dynamic and static flight characteristics. The designers of NELDA believe that their successful commuter electric airplane design will be part of the beginning of new, improved, clean aerial transportation.},

keywords = {03. Center Of Gravity, 10. Weight Engineering - Aircraft Design, Student Papers},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3762,

title = {3762. Artificial Intelligence Techniques for Ship Weight Estimation and Calculation},

author = {Upendra Malla},

url = {https://www.sawe.org/product/paper-3762},

year  = {2021},

date = {2021-11-01},

urldate = {2021-11-01},

booktitle = {2021 SAWE Tech Fair},

pages = {9},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Virtual Conference},

abstract = {The advancement of computing and data analysis tools gave rise to the development of Artificial Intelligence (AI) tools. The ship weight estimation and calculation are a simple and tedious process which requires a qualitative weight budgets and quantitative calculations. The evolution of ship weight estimation and calculation using Artificial Intelligence techniques is discussed in the paper and compared with the existing techniques used in the shipping industry. Currently there are several in-house tools and software’s which are utilized by design firms and shipyards for the mass properties estimation / calculation, but these tools are not built with any intelligence to make the weight estimate accurate and effective. The implementation of Artificial Intelligence algorithms for the ship weight estimation by considering the constraints like class rules, standards, guidelines etc. 

In this paper at the end, it shows the cost and time savings involved by the implementation of Artificial Intelligence techniques in the ship weight estimate program by means of an example AI tool.},

keywords = {12. Weight Engineering - Computer Applications},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3765,

title = {3765. Mass Properties and Automotive Directional Stability},

author = {B P Wiegand},

url = {https://www.sawe.org/product/paper-3765},

year  = {2021},

date = {2021-11-01},

urldate = {2021-11-01},

booktitle = {2021 SAWE Tech Fair},

pages = {61},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Virtual Conference},

abstract = {The quantification of automotive directional stability may be expressed through various stability metrics, but perhaps the most basic of these automotive stability metrics is the “Understeer Gradient” (Kus). The Understeer Gradient (in degrees or radians per unit gravity) appears extremely uncomplicated when viewed in its most common formulation. Kus =[ Wf / gCsf - Wr / gCsr ] 

This metric appears to depend only on the front and rear axle weight loads (Wf, Wr), and on the front and rear axle cornering stiffnesses (Csf, Csr). However, those last quantities vary with lateral acceleration, and the nature of that variation is dependent upon many other parameters of which some of the most basic are: Total Weight, Sprung Weight, Unsprung Weight, Forward Unsprung Weight, Rear Unsprung Weight, Total Weight LCG, Sprung Weight LCG, Total Weight VCG, Sprung Weight VCG, Track, Front Track, Rear Track, Roll Stiffness, Front Roll Stiffness, Rear Roll Stiffness, Roll Axis Height, Front Roll Center Height, and Rear Roll Center Height. Note that exactly half of these automotive directional stability parameters as listed herein are mass properties. 

The purpose of this paper is to explore, through a skidpad simulation, the relative sensitivity of automotive directional stability (as quantified through the Understeer Gradient) to variation in each of the noted vehicle parameters, with special emphasis on the mass property parameters. 

The simulation is constructed in a spreadsheet format from the relevant basic automotive dynamics equations; the normal and lateral loads on the tires are determined as the lateral acceleration is increased incrementally by a small amount (thereby maintaining a “quasi-static” or “steady-state” condition). The normal loads are used for the calculation of the lateral traction force potentials at each tire, with the required (centripetal) lateral traction forces apportioned accordingly. From those required (actual) lateral tire forces the corresponding tire cornering stiffnesses are determined; this determination is based upon a tire model developed through a regression analysis of tire test data. 

This construction of a fairly comprehensive lateral acceleration simulation from basic automotive dynamic relationships, instead of depending upon commercial automotive software such as “CarSim” (vehicle model) and Pacjeka “Magic Formula” (tire model), constitutes a unique aspect of this paper; this return to basics hopefully provides a clearer view and understanding of the results than would be the case otherwise. Even more unique is this paper’s emphasis on, and exploration of, the role specific mass property parameters play in determining automotive directional stability.},

keywords = {31. Weight Engineering - Surface Transportation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3768,

title = {3768. Mass Properties Reporting},

author = {Yiyuan Ma and Jin Yan and Ali Elham},

url = {https://www.sawe.org/product/paper-3768},

year  = {2021},

date = {2021-11-01},

urldate = {2021-11-01},

booktitle = {2021 SAWE Tech Fair},

pages = {28},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Virtual Conference},

abstract = {The Ultra-High Aspect Ratio Wing (UHARW) concept can improve the aircraft's aerodynamic efficiency and reduce fuel consumption. The Twin-Fuselage (TF) configuration is one of the most promising concepts for the UHARW design to reduce the wing bending moments and shear forces. This paper presents the development of a semi-empirical method for the weight estimation of TF aircraft in the initial sizing stage. A physics-based wing weight estimation method is improved for higher aerodynamic analysis fidelity and composite materials, which is used in the design of experiments and the results are applied for regression analysis to establish a semi-empirical method. Eventually, the established semi- empirical weight estimation method is integrated into a TF aircraft conceptual design and performance analysis framework, and a mid-range TF aircraft and a long-range TF aircraft are designed and sized to illustrate its application and efficiency in rapidly estimating the TF aircraft weight breakdown.},

keywords = {10. Weight Engineering - Aircraft Design, 11. Weight Engineering - Aircraft Estimation, Student Papers},

pubstate = {published},

tppubtype = {inproceedings}

}