Naval Shock Analysis (DDAM) Using SOLIDWORKS Simulation

Article by Shaun Bentley on Mar 03, 2020

The Dynamic Design Analysis Method (DDAM) is a methodology developed by the U.S. Navy for testing shock loading from underwater explosions. SOLIDWORKS Simulation Premium can test your designs using this method. 

In order to run an analysis using DDAM, the following four steps must be completed in the following order:

  1. Modal Analysis
  2. Shock Load Generation 
  3. Response Spectrum Analysis
  4. Results Reporting

Step 1: Modal Analysis

SOLIDWORKS Simulation calculates resonant frequencies and mass participations. Below are the modal results a 3’ x 4’ aluminum sheet mounted on the deck of a ship.

SOLIDWORKS Simulation Modal

SOLIDWORKS Simulation Modal Results

Resonant Frequencies and Mass Participations with SOLIDWORKS Simulation

Resonant Frequencies and Mass Participations 

Step 2: Shock Load Generation

SOLIDWORKS Simulation users will need to consult the equations listed in the NRL Memorandum Report 1396 in order to generate their shock loads. We have created a spreadsheet as an example of how this could be done.

Step 3: Response Spectrum Analysis

Once you have the shock load from the previous step, you can now run a Response Spectrum Analysis and measure peak stresses and deflections. Here are what the results look like.


SOLIDWORKS Simulation Peak displacement of 1.211 inches
SOLIDWORKS Simulation: Peak displacement of 1.211 inches


Step 4: Results Reporting

SOLIDWORKS Simulation produces results which should satisfy the requirements of DI-ENVR-81030 .

Some customization of the SOLIDWORKS Simulation results and exports will likely be needed to make sure the data is recognized, and the requirements are completely satisfied. SOLIDWORKS Simulation can export a printout of the input data ( SS_Sample.DAT ) in several formats to include details like node point locations.

SOLIDWORKS Simulation exports

Nodal forces and connector forces may be missing from these exports and may need to be exported manually from some plots in the SOLIDWORKS Simulation interface. 


For users who are ok with generating their own shock loads and who prefer the intuitive SOLIDWORKS environment, SOLIDWORKS Simulation Premium can run your DDAM studies. This tool makes it easy to test design changes since studies can be automatically re-meshed and re-run after using SOLIDWORKS to change features and dimensions in your model.

Want to learn more about performing studies in SOLIDWORKS Simulation? Check out the related links below.

More SOLIDWORKS Simulation Studies

Understanding the Rattleback Mystery with SOLIDWORKS Motion

Piecewise Nonuniform Pressure in SOLIDWORKS Simulation

Introduction to Structural Analysis Using SOLIDWORKS Simulation Tools

7 Steps to Perform a Fatigue Analysis in SOLIDWORKS Simulation

SOLIDWORKS Simulation Frequency Analysis Comparison Between FEA & Real Life



About Shaun Bentley

Shaun Bentley is passionate about applied mathematics and engineering, which led him to pursue and understand real world applications of FEA, CFD, kinematics, dynamics, and 3D & 2D modeling. He teaches many simulation classes to both new and advanced users attending training at GoEngineer. Since 2006, Shaun has been working with simulation tools to solve real world engineering problems. With every new project, he seeks to find ways to push simulation to its uppermost limits, even going so far as to write bespoke code and macros. He has passed the Michigan FE exam and mentors or consults for virtually any industry that uses SOLIDWORKS, especially automotive and automated tools. He is a speed 3D modeling champion and one of the first Certified SOLIDWORKS Experts in Simulation in the world.

View all posts by Shaun Bentley