Coupled Loads Analysis

Rapidly Predict Critical Loads

Coupled loads analysis (CLA) is a critical process for many high-technology systems including launch vehicles and satellites. CLA predicts responses caused by major dynamic and quasistatic loading events such as liftoff, gust, buffet, and engine startup and shutdown. CLA helps to minimize risk and maximize the probability of mission success.


Advanced CLA Methods


Quartus Engineering has a wide range of capabilities for rapidly and accurately performing coupled loads analysis. Specific features include:

  • Modal synthesis methods including Craig-Bampton, Rubin-MacNeal residual flexibility, and others
  • Superelement and substructure software for model processing and assembly
  • Damping synthesis algorithms including Hruda-Benfield, triple matrix product, and energy participation methods
  • Efficient modal transient analysis for systems with diagonal or coupled damping matrices
  • Residual vector and mode acceleration methods for accurate data recovery
  • Hydroelastic analysis software for slosh and coupled fluid/structure modes of liquid propellant launch vehicles and satellite tanks

Extensive CLA Experience

Quartus engineers have performed coupled loads for a wide range of launch vehicles and satellites including:


  • Space Shuttle
  • Titan IV/Centaur
  • Titan 34D
  • Atlas
  • Taurus
  • Pegasus


  • Cassini
  • Galileo
  • JWST
  • Cygnus
  • Planet SkySat
  • Dawn
  • Orion
  • GEOStar 1-3
  • MiTEx

LV and SC Model Processing


Quartus has extensive experience in processing launch vehicle and spacecraft models. Special capabilities include:

  • Craig-Bampton and bulk data model formats
  • Model checking procedures to examine numerical grounding, rigid body mass, and effective mass
  • Data recovery matrix (DRM) generation, checking, and processing
  • Results postprocessing and visualization
  • Pretest analysis, test-analysis correlation, and model updating for modal survey tests

Software Tools

Quartus has an extensive array of software programs and custom tools for performing coupled loads analysis. Commercial software includes MSC/NASTRAN, NX NASTRAN, and Matlab. Quartus also has a library of custom software including FEMAP APIs, C and FORTRAN programs, DMAP alters, and Matlab scripts to assist in CLA model and data processing.

Technology Transfer and Outsourcing

Quartus can work with clients in a variety of methods including:

  • Technology transfer of advanced methods to improve capabilities and productivity
  • Complimenting in-house resources to accelerate schedules and handle peak workloads
  • Performing CLA on an outsourcing basis
  • Providing independent verification and validation (IV&V) of methods, models, and results

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Who We Are

Quartus Engineering Incorporated was founded in 1997 to provide quality advanced engineering services. Quartus specializes in the design and analysis of mechanical systems using computer-aided technologies. We are committed to serving the needs of the engineering community in a timely and cost-effective manner. Download our brochure.

SAN DIEGO 9689 Towne Centre Dr San Diego, California 92121 T (858) 875-6000   MORE INFO
HERNDON 2300 Dulles Station Blvd Suite 650 Herndon, Virginia 20171 T (571) 266-5300 MORE INFO