BS ISO 14953:2024
Space systems. Structural design. Determination of loading levels for static qualification testing of launch vehicles

Standard No.

BS ISO 14953:2024

Release Date

2024

Published By

British Standards Institution (BSI)  GB  /  BSI

Latest

BS ISO 14953:2024

Introduction

Analysis of the core content of the standard

BS ISO 14953:2024 is the UK's national standard transformation of ISO 14953:2024, which completely replaces the 2000 version of the standard. This standard is specifically aimed at the static certification test of the structure of spacecraft such as launch vehicles, and establishes a systematic load level determination method.

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Key Technical Elements

Certification Test Load Calculation Formula

The core calculation formula proposed in the standard is: P_Q = P_lim × J_C, where:

• P_Q: Corrected external load (force/torque/pressure) for certification test
• P_lim: Design limit load
• J_C: Corrected safety factor

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Comparison of Correction Factor Systems

Correction Factor	Applicable Objects	Calculation Method	Main Changes in the 2024 Edition
Kmin (Thickness)	Metal structure	Specimen thickness/minimum allowable manufacturing thickness	New instructions for collaborative use with Kσ
Kadj (Adjacent structure)	All structures	σflight/σtest (≥1)	Refine boundary condition simulation requirements
Kimp (Geometric imperfections)	Buckling-sensitive structure	Fm imp/Fd imp	New factors in the 2024 version

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Standard evolution analysis

Main improvements compared to the 2000 version:

1. The calculation formula of the modified safety factor J_C is changed to a full multiplication expression
2. New geometric defect correction factor K_imp
3. Clarify the coordinated application rules of thickness correction factor and dispersion correction factor

These changes reflect the higher requirements for manufacturing process deviations and actual defect effects in the field of spacecraft structure testing.

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Implementation Suggestions

Key Steps

• Identify critical areas under all possible failure modes
• Establish a special analysis process for each correction factor
• Give priority to using flight configuration boundary conditions for test simulation

Notes

• When the calculated result of K_adj is <1, it is forced to be 1
• K_min of non-metallic structures is 1 by default
• K_{imp can be ignored for non-buckling sensitive structures}

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Application Case

In the static test of a launch vehicle fuel tank:

• Using 2.5mm specimen (minimum allowable thickness 2.0mm) → K_min=1.25
• Test temperature 20℃ vs flight temperature -50℃ → Material property ratio K_θ=1.18
• Measured geometric defects reduce the buckling load by 12% → K_imp=1.14
• The final corrected safety factor J_C is 37.6%
higher than the design value

BS ISO 14953:2024 history

• 2024 BS ISO 14953:2024 Space systems. Structural design. Determination of loading levels for static qualification testing of launch vehicles
• 2000 BS ISO 14953:2000 Space systems. Structural design. Determination of loading levels for static qualification testing of launch vehicles

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