Search NASA⌕ Search

SEARCH · Search NASA

Results for “Design Load”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

Simple Formulas and Results for Buckling-Resistance and Stiffness Design of Compression-Loaded Laminated-Composite Cylinders

Simple formulas for the buckling stress of homogeneous, specially orthotropic, laminated-composite cylinders are presented. The formulas are obtained by using nondimensional parameters and equations that facilitate general validation, and are validated against the exact solution for a wide range of cylinder geometries and laminate constructions. Results are presented that establish the ranges of the nondimensional parameters and coefficients used. General results, given in terms of the nondimensional parameters, are presented that encompass a wide range of geometries and laminate constructions. These general results also illustrate a wide spectrum of behavioral trends. Design-oriented results are also presented that provide a simple, clear indication of laminate composition on critical stress, critical strain, and axial stiffness. An example is provided to demonstrate the application of these results to thin-walled column designs.

Nemeth, Michael P.↗
NASA NTRS1993

Viper cabin-fuselage structural design concept with engine installation and wing structural design

This report describes the process and considerations in designing the cabin, nose, drive shaft, and wing assemblies for the 'Viper' concept aircraft. Interfaces of these assemblies, as well as interfaces with the sections of the aircraft aft of the cabin, are also discussed. The results of the design process are included. The goal of this project is to provide a structural design which complies with FAR 23 requirements regarding occupant safety, emergency landing loads, and maneuvering loads. The design must also address the interfaces of the various systems in the cabin, nose, and wing, including the drive shaft, venting, vacuum, electrical, fuel, and control systems. Interfaces between the cabin assembly and the wing carrythrough and empennage assemblies were required, as well. In the design of the wing assemblies, consistency with the existing cabin design was required. The major areas considered in this report are materials and construction, loading, maintenance, environmental considerations, wing assembly fatigue, and weight. The first three areas are developed separately for the nose, cabin, drive shaft, and wing assemblies, while the last three are discussed for the entire design. For each assembly, loading calculations were performed to determine the proper sizing of major load carrying components. Table 1.0 lists the resulting margins of safety for these key components, along with the types of the loads involved, and the page number upon which they are discussed.

Marchesseault, B.↗
NASA NTRS1920

Static testing and proposed standard specifications

Static tests fall into two groups, the first of which is designed to load all members of the structure approximately in accordance with the worst loads which they carry in flight, while the second is directed to the testing of specific members which are suspected of weakness and which are difficult to analyze mathematically. The nature of the loading in the second type is different for every different test, but the purpose of the first is defined clearly enough to permit the adoption of some standard set of loading specifications, at least for airplanes of normal design. Here, an attempt is made to carry through an analysis leading to such a standard, the goal being the determination of a load which will simultaneously impose on every member of the airplane structure a stress equal to the worst it will carry in flight.

Warner, E P↗
NASA NTRS1974

Modular, high power, variable R dynamic electrical load simulator

The design of a previously developed basic variable R load simulator was entended to increase its power dissipation and transient handling capabilities. The delivered units satisfy all design requirements, and provides for a high power, modular simulation capability uniquely suited to the simulation of complex load responses. In addition to presenting conclusions and recommendations and pertinent background information, the report covers program accomplishments; describes the simulator basic circuits, transfer characteristic, protective features, assembly, and specifications; indicates the results of simulator evaluation, including burn-in and acceptance testing; provides acceptance test data; and summarizes the monthly progress reports.

Joncas, K. P.↗
NASA NTRS1971

Structural efficiencies of five compression panels with curved elements

Structural-efficiency analyses are used to determine the minimum-mass proportions of some panel configurations loaded in uniaxial compression. Five panel constructions, four of which incorporate circular-arc elements and the other a beaded-web corrugation, are shown to have improved structural efficiencies over conventional configurations. In addition to the structural-efficiency equations, which give the mass equivalent flat-plate thickness of the panel necessary to carry a given load, related design equations for calculating the cross-sectional dimensions of these minimum-mass panels are presented. The upper and lower limits of loading, where the design constraints of minimum gage or material yield strength become the dominant design conditions, are established and the corresponding design equations which are applicable outside these limits are also presented.

Giles, G. L.↗
NASA NTRS1987

Initial dynamic load estimates during configuration design

This analysis includes the structural response to shock and vibration and evaluates the maximum deflections and material stresses and the potential for the occurrence of elastic instability, fatigue and fracture. The required computations are often performed by means of finite element analysis (FEA) computer programs in which the structure is simulated by a finite element model which may contain thousands of elements. The formulation of a finite element model can be time consuming, and substantial additional modeling effort may be necessary if the structure requires significant changes after initial analysis. Rapid methods for obtaining rough estimates of the structural response to shock and vibration are presented for the purpose of providing guidance during the initial mechanical design configuration stage.

Schiff, Daniel↗
NASA NTRS1989

Probabilistic design analysis using Composite Loads Spectra (CLS) coupled with Probabilistic Structural Analysis Methodologies (PSAM)

Composite loads spectra (CLS) were applied to generate probabilistic loads for use in the PSAM nonlinear evaluation of stochastic structures under stress (NESSUS) finite element code. The CLS approach allows for quantifying loads as mean values and distributions around a central value rather than maximum or enveloped values typically used in deterministic analysis. NESSUS uses these loads to determine mean and perturbation responses. These results are probabilistically evaluated with the distributional information from CLS using a fast probabilistic integration (FPI) technique to define response distributions. The main example discussed describes a method of obtaining load descriptions and stress response of the second-stage turbine blade of the Space Shuttle Main Engine (SSME) high-pressure fuel turbopump (HPFTP). Additional information is presented on the on-going analysis of the high pressure oxidizer turbopump discharge duct (HPOTP) where probabilistic dynamic loads have been generated and are in the process of being used for dynamic analysis. Example comparisons of load analysis and engine data are furnished for partial verification and/or justification for the methodology.

Newell, J. F.↗
NASA NTRS1993

A comparison of hand grasp breakaway strengths and bare-handed grip strengths of the astronauts, SML 3 test subjects, and the subjects from the general population

Astronauts have the task of retrieving and deploying satellites and handling massive objects in a around the payload bay. Concerns were raised that manual handling of such massive objects might induce loads to the shuttle suits exceeding the design-certified loads. The Crew and Thermal Division of NASA JSC simulated the satellite handling tasks (Satellite Manload Tests 1 and 3) and determined the maximum possible load that a suited member could impart onto the suit. In addition, the tests revealed that the load to the suit by an astronaut could be calculated from the astronaut's maximum hand grasp breakaway strength. Thus, this study was conducted to document that hand grasp breakaway strengths of the astronauts who were scheduled to perform EVA during the upcoming missions. In addition, this study verified whether the SML 3 test results were sufficient for documenting the maximum possible load. An attempt was made to predict grasp strength from grip strength and hand anthropometry. Based on the results from this study, the SML 3 test results were deemed sufficient to document the maximum possible load on the suit. Finally, prediction of grasp strength from grip strength was not as accurate as expected. Hence, it was recommended that grasp strength be collected from the astronauts in order to obtain accurate load estimation.

Rajulu, Sudhakar L.↗
NASA NTRS1951

Strain-Gage Measurements of Buffeting Loads on a Jet-Powered Bomber Airplane

Buffet boundaries, buffeting-load increments for the stabilizers and elevators, and buffeting bending-moment increments for the stabilizers and wings as measured in gradual maneuvers for a jet-powered bomber airplane are presented. The buffeting-load increments were determined from strain-gage measurements at the roots or hinge supports of the various surfaces considered. The Mach numbers of the tests ranged from 0.19 to 0.78 at altitudes close to 30,000 feet. The predominant buffet frequencies were close to the natural frequencies of the structural components. The buffeting-load data, when extrapolated to low-altitude conditions, indicated loads on the elevators and stabilizers near the design limit loads. When the airplane was held in buffeting, the load increments were larger than when recovery was made immediately.

Aiken, William S., Jr.↗