Engineering Services Spotlight: Multi-Body Dynamics Analysis

March 26, 2014

Modeling and analysis of complex multi-body dynamics problems is an important aspect of automotive suspension, machinery, gun mechanism, and a widening range of complex mechanical systems design problems. The NTS Engineering Services group in Dana Point, CA has recently added, developed expertise of use in, and begun applying a new software tool, MSC Adams, to attack these problems. MSC Adams is a highly evolved multi-body dynamics solver that can leverage 3D CAD models of customer products and then “bring them to life” with the addition of accurate mass properties, part-to-part contact/interface models, constraints, and input forces. Although most CAD software has add-on or built-in motion analysis tools, MSC Adams takes it to the next level of capability in terms of complexity and numerical solver efficiency.

Our United States Marine Corps customer recently employed NTS Engineering Services to perform gun system mechanism dynamics analysis of the .50 caliber M2 HB weapon. They were looking to determine the dynamic structural loads imparted by the weapon to their new polymer based cartridge case design being developed to reduce the overall weight of the .50 caliber ammunition family.  After preparing a detailed 3D CAD model of the M2 HB gun system and performing interior ballistics analysis of a cartridge being fired, NTS developed a highly accurate mechanism model for the gun as shown in Figure 1 below.

ulti-Body Dynamics Figure 1
Figure 1. Screen Shot of Multi-Body Dynamics Analysis Model of the M2 HB Gun

In partnership with our test facility proving ground in Camden, AR, we then performed highly instrumented (with accelerometers and high speed digital video) gun system testing of the standard and new cartridge designs. We obtained accurate barrel acceleration time histories and bolt displacement time histories for direct comparison with the model.  The resulting agreement between the model and experimental data was excellent as shown in Figure 2.1 and 2.2 below.

Multi-Body Dynamics Data Comparison 1
Figure 2.1 Comparisons with Experimental Data
Multi-Body Dynamics Experimental Data Comparison
Figure 2.2 Comparisons with Experimental Data

The acceleration time history loads imparted to the cartridge assembly derived from this model then allowed NTS to perform an accurate dynamic structural analysis of the polymer based cartridge design with a high degree of confidence.

If you have any questions related to the MSC Adams software or engineering services please contact NTS Dana Point at 949-429-8602 or view the facility overview at


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