SMC-S-004
INDEPENDENT STRUCTURAL LOADS ANALYSIS
Year: 2008
Abstract: Introduction
During launch and ascent, a spacecraft and its launch vehicle experience severe structural loads. These loads represent the principal design requirements for most of the launch vehicle and spacecraft structure. Critical load-producing events include liftoff, atmospheric flight (static aeroelastic, gust/turbulence, buffet and other load contributors), engine ignitions and shutdowns, and staging and separation events.
The structural design and validation process involves independent contractors and organizations, and numerous technical disciplines such as structures, structural dynamics, fluids, propulsion, controls, flight mechanics, statistics, and atmospheric sciences. The determination of structural dynamic properties, loads, stresses, and structural margins of safety requires specialized testing, extremely large mathematical models, and complex analyses. Significantly complicating the process is the fact that the fully integrated spacecraft/launch vehicle system needs to be addressed, and the integrated system cannot be tested prior to flight. Further complications arise because significant engineering judgment is involved, no single organization controls the overall structural dynamic properties of the integrated system, and schedule and cost considerations play major roles.
Launch and ascent structural loads are functions of the dynamic properties of the integrated spacecraft/launch vehicle system. Therefore, design changes in one element can result in load changes in all elements, and modeling errors in one element can result in load prediction errors in all elements. Because the dynamic properties of each element depend upon the structural design of that element, the design and analysis process is iterative.
As a result of the above considerations and lessons learned, a formal Load Cycle Process was developed for use on Air Force programs (Fig. 1, Refs. 1 and 2). In 1979, the requirement to follow this process was levied on both the spacecraft and launch vehicle program offices by SAMSO Regulation 550-5, Commander's Policy on "Independent Structural Loads Analysis of Integrated Payload and Launch Vehicle Systems" (Ref. 3). SAMSO Pamphlet 800-5 (Ref. 4), developed in 1975, was specified in the Commander's Policy to aid program offices in implementation of the policy. The policy was suspended in the nineties as part of the government effort to reduce military specifications.
SAMSO Regulation 550-5 provided uniformity in the structural design and evaluation of both spacecraft and launch vehicle structure, and can be credited to a great extent with the success of the structural systems within its purview. It also helped ensure that all involved parties understood their responsibilities to each other, and minimized the potential impacts to the government when problems arose. Since suspension of the regulation, a number of issues have arisen. These are addressed herein as an updated version of SAMSO Pamphlet 800-5 that retains the principal ingredients of the original document and accounts for lessons learned since the time it was written. The intent of this document is to serve as a source of requirements for implementation of the Load Cycle Process and its most critical elements.
During launch and ascent, a spacecraft and its launch vehicle experience severe structural loads. These loads represent the principal design requirements for most of the launch vehicle and spacecraft structure. Critical load-producing events include liftoff, atmospheric flight (static aeroelastic, gust/turbulence, buffet and other load contributors), engine ignitions and shutdowns, and staging and separation events.
The structural design and validation process involves independent contractors and organizations, and numerous technical disciplines such as structures, structural dynamics, fluids, propulsion, controls, flight mechanics, statistics, and atmospheric sciences. The determination of structural dynamic properties, loads, stresses, and structural margins of safety requires specialized testing, extremely large mathematical models, and complex analyses. Significantly complicating the process is the fact that the fully integrated spacecraft/launch vehicle system needs to be addressed, and the integrated system cannot be tested prior to flight. Further complications arise because significant engineering judgment is involved, no single organization controls the overall structural dynamic properties of the integrated system, and schedule and cost considerations play major roles.
Launch and ascent structural loads are functions of the dynamic properties of the integrated spacecraft/launch vehicle system. Therefore, design changes in one element can result in load changes in all elements, and modeling errors in one element can result in load prediction errors in all elements. Because the dynamic properties of each element depend upon the structural design of that element, the design and analysis process is iterative.
As a result of the above considerations and lessons learned, a formal Load Cycle Process was developed for use on Air Force programs (Fig. 1, Refs. 1 and 2). In 1979, the requirement to follow this process was levied on both the spacecraft and launch vehicle program offices by SAMSO Regulation 550-5, Commander's Policy on "Independent Structural Loads Analysis of Integrated Payload and Launch Vehicle Systems" (Ref. 3). SAMSO Pamphlet 800-5 (Ref. 4), developed in 1975, was specified in the Commander's Policy to aid program offices in implementation of the policy. The policy was suspended in the nineties as part of the government effort to reduce military specifications.
SAMSO Regulation 550-5 provided uniformity in the structural design and evaluation of both spacecraft and launch vehicle structure, and can be credited to a great extent with the success of the structural systems within its purview. It also helped ensure that all involved parties understood their responsibilities to each other, and minimized the potential impacts to the government when problems arose. Since suspension of the regulation, a number of issues have arisen. These are addressed herein as an updated version of SAMSO Pamphlet 800-5 that retains the principal ingredients of the original document and accounts for lessons learned since the time it was written. The intent of this document is to serve as a source of requirements for implementation of the Load Cycle Process and its most critical elements.
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contributor author | AIR FORCE - 02 - Air Force Network Integration Center (AFNIC) | |
date accessioned | 2017-09-04T18:16:34Z | |
date available | 2017-09-04T18:16:34Z | |
date copyright | 06/13/2008 | |
date issued | 2008 | |
identifier other | HNDQJEAAAAAAAAAA.pdf | |
identifier uri | http://yse.yabesh.ir/std/handle/yse/199471 | |
description abstract | Introduction During launch and ascent, a spacecraft and its launch vehicle experience severe structural loads. These loads represent the principal design requirements for most of the launch vehicle and spacecraft structure. Critical load-producing events include liftoff, atmospheric flight (static aeroelastic, gust/turbulence, buffet and other load contributors), engine ignitions and shutdowns, and staging and separation events. The structural design and validation process involves independent contractors and organizations, and numerous technical disciplines such as structures, structural dynamics, fluids, propulsion, controls, flight mechanics, statistics, and atmospheric sciences. The determination of structural dynamic properties, loads, stresses, and structural margins of safety requires specialized testing, extremely large mathematical models, and complex analyses. Significantly complicating the process is the fact that the fully integrated spacecraft/launch vehicle system needs to be addressed, and the integrated system cannot be tested prior to flight. Further complications arise because significant engineering judgment is involved, no single organization controls the overall structural dynamic properties of the integrated system, and schedule and cost considerations play major roles. Launch and ascent structural loads are functions of the dynamic properties of the integrated spacecraft/launch vehicle system. Therefore, design changes in one element can result in load changes in all elements, and modeling errors in one element can result in load prediction errors in all elements. Because the dynamic properties of each element depend upon the structural design of that element, the design and analysis process is iterative. As a result of the above considerations and lessons learned, a formal Load Cycle Process was developed for use on Air Force programs (Fig. 1, Refs. 1 and 2). In 1979, the requirement to follow this process was levied on both the spacecraft and launch vehicle program offices by SAMSO Regulation 550-5, Commander's Policy on "Independent Structural Loads Analysis of Integrated Payload and Launch Vehicle Systems" (Ref. 3). SAMSO Pamphlet 800-5 (Ref. 4), developed in 1975, was specified in the Commander's Policy to aid program offices in implementation of the policy. The policy was suspended in the nineties as part of the government effort to reduce military specifications. SAMSO Regulation 550-5 provided uniformity in the structural design and evaluation of both spacecraft and launch vehicle structure, and can be credited to a great extent with the success of the structural systems within its purview. It also helped ensure that all involved parties understood their responsibilities to each other, and minimized the potential impacts to the government when problems arose. Since suspension of the regulation, a number of issues have arisen. These are addressed herein as an updated version of SAMSO Pamphlet 800-5 that retains the principal ingredients of the original document and accounts for lessons learned since the time it was written. The intent of this document is to serve as a source of requirements for implementation of the Load Cycle Process and its most critical elements. | |
language | English | |
title | SMC-S-004 | num |
title | INDEPENDENT STRUCTURAL LOADS ANALYSIS | en |
type | standard | |
page | 21 | |
status | Active | |
tree | AIR FORCE - 02 - Air Force Network Integration Center (AFNIC):;2008 | |
contenttype | fulltext |