SAWE Technical Papers

@inproceedings{3773,

title = {3773. SAWE’s New Technical Paper “Groups”},

author = {Andreas Schuster},

url = {https://www.sawe.org/product/paper-3773},

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 = {Over the last 80 years, all SAWE technical papers are indexed by a Category system to make searches easier. The current index has evolved to meet the needs of the authors and researchers. However, some of the categories have become outdated as technology has changed, like categories are not grouped together, and there is no definition of what goes into a specific category. The SAWE Technical Committee under the leadership of the VP-Technical Director completed a project to modernize the quick search capability of Category indexing and to define the content of each category. This paper presents the “Group” indexing listing, considerations of alternative group and categories and the implementation steps that are required over the next few years. The title Group is used to differentiate it from the legacy Category index and to mitigate the use of “new Category”, since in 20 years it will be old too.},

keywords = {SAWE Inc.},

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{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{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{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{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{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{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{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{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{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{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{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{3774,

title = {3774. Weight Control For Floating Wind Installation},

author = {A. P. Crowle and P. R. Thies},

url = {https://www.sawe.org/product/paper-3774},

year  = {2021},

date = {2021-11-01},

urldate = {2021-11-01},

booktitle = {2021 SAWE Tech Fair},

pages = {10},

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

address = {Virtual Conference},

abstract = {Floating offshore wind is a growing market within the renewable energy sector. The floating offshore wind turbines give access to deeper water sites, with minimal visual impact from land. The paper includes the weight control requirements for Spars, barges, semi submersibles and Tension Leg Platforms (TLPs) as floating wind platforms. 

There are weight control challenges for the various substructure types during the temporary phases of construction and offshore installation. An accurate assessment of the buoyancy of the floating wind turbine for different drafts and trims is required. Allowances need to be included in the weight calculation for temporary buoyancy, sea-fastenings and grillage. 

Weight control for installation has an influence on the weather window for the floating substructures during transportation to the offshore site and mooring and electrical connection. The paper will cover weight calculation methods during early design, detailed design, construction, installation, operation and demolition. 

The installation process for a floating wind turbine varies with substructure type and this paper will give an overview of the weight control requirements for loadout, ocean transport and mooring connection. The floating offshore wind turbine weight and centre of gravity has a direct bearing on draft, intact stability and motions. As part of the weight control process the centre of gravity and radii of gyration need to be accurately determined for each stage of the installation.},

keywords = {24. Weight Engineering - System Design, 35. Weight Engineering - Offshore, Marine, Student Papers},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3772,

title = {3772. Scenario-based Prediction of Lightweight Costs - an Approach across Industries},

author = {Florian Wätzold},

url = {https://www.sawe.org/product/paper-3772},

year  = {2021},

date = {2021-11-01},

urldate = {2021-11-01},

booktitle = {2021 SAWE Tech Fair},

pages = {38},

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

address = {Virtual Conference},

abstract = {To decide on which technology is best for a vehicle in development, technical and economical constraints need to be considered. The objective of this paper is to provide a generic, conceptual approach to estimating the value (€ or $) per weight unit (kg or lb), referred as lightweight cost, for all industries. It combines general project management and cost estimation techniques with mass property management. As cost and weight are unknown until the actual weighing or billing, this paper focuses on scenario-based assumptions. For an easy understanding, this lens is applied to a recently developed battery concept. 

The described approach integrates basic project management processes such as risk management, estimation considerations and cost assessment. In this pursuit, mass and cost are rolled-up based on the breakdown structure. Taking the uncertainties into account a most likely, best, and worst case are evaluated and a cone of respective lightweight cost is generated. For the ease of use in industrial daily business exactly one value per pound for decision making is derived, condensing the lightweight cost range by superimposing the mass and cost according to their specific scenario probability.},

keywords = {29. Weight Value-Of-Pound, Student Papers},

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}

}

@inproceedings{3771,

title = {3771. A Look at Inclining Experiment Heel Angles: Measurement Tools and Sensitivity},

author = {David Tellet},

url = {https://www.sawe.org/product/paper-3771},

year  = {2021},

date = {2021-11-01},

urldate = {2021-11-01},

booktitle = {2021 SAWE Tech Fair},

pages = {27},

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

address = {Virtual Conference},

abstract = {An inclining experiment is used to indirectly measure the vertical center of gravity of a ship by measuring resultant heel angles for a given weight moved athwartships. The methods for measuring these angles are considered tried and true even though the uncertainties of their accuracy and precision are not well understood. This paper explores the impact of errors from traditional inclining methods and compares them with modern methods. The paper looks at a simulated inclining experiment and explores the change in results when errors are introduced into the measurements. It then looks at electronic inclinometers used in an actual inclining and discusses how that data can be analyzed and how that might affect the results of the experiment. Finally the paper discusses the advantages and disadvantages of old and new methods and provides recommendations for improved results from future inclinings.},

keywords = {03. Center Of Gravity, Marine},

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{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{3736,

title = {3736. Hydrogen Fuel Cell Power System Weight Challenges in VTOL Aircraft},

author = {Greg Ray and Joseph D. Rainville},

url = {https://www.sawe.org/product/paper-3736},

year  = {2020},

date = {2020-07-01},

booktitle = {2020 SAWE Tech Fair},

pages = {16},

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

address = {Virtual Conference},

abstract = {The 'More Electric Aircraft' movement is maturing past actuation, flight controls and backup power solutions. Starting with Unmanned Aerial Vehicles (UAV) and now growing into the passenger vehicle market, vertical lift aircraft engineers are developing electric driven propulsion systems.One of major limitations with electrification is endurance or range. Batteries only offer so much energy capacity before mass becomes a limiting factor. Hydrogen fuel cells offer another solution for on board electrical generation but present many of their own technical challenges.In cases of typical passenger vertical lift aircraft, electrification supplants traditional gas turbines and liquid fuel tanks with electric motors, power electronics, and either batteries or hydrogen fuel cells for an energy source. For Class I UAVs (55 lbs. total weight) or Class II UAVs (up to 300 lbs. total weight), batteries could be replaced by smaller, simplified fuel cells, electronics and hydrogen storage.The electric powertrain evolution will have a strong impact on several aspects of aircraft technology development, especially mass properties and center of gravity as the emerging technology is not limited to time honored positions and locations of legacy components. This paper researches some of the risks and opportunities with electrifying the propulsion systems of vertical lift aircraft.},

keywords = {11. Weight Engineering - Aircraft Estimation, 34. Advanced Design},

pubstate = {published},

tppubtype = {inproceedings}

}