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Damage Tolerance Analysis, Stress Tool and Structural Testing

Damage Tolerance Analysis

MERC developed a finite element model of the entire C-130 fuselage, empennage, and center wing. We also performed Damage Tolerance Analyses on more than a dozen critical areas on the fuselage and developed and/or revised the inspection intervals on these areas based on the detailed analyses. The delivered finite element model generated enormous cost savings for the customer.

Stress Tool

Stress Tool allows engineers to navigate through a list of aircraft parts quickly and efficiently.

The Stress Tool also offers engineers the capability to see cross-sectional views of selected parts, allowing engineers to see thicknesses throughout selected parts. The Stress Viewer allows engineers to choose an individual part from the list of aircraft parts and view stresses and other various properties associated with that part.

The connected parts viewer shows all parts connected to a selected component so that engineers may see the surrounding structure of a part. The intent of the configuration tool is to allow users to easily and rapidly identify and measure available space in each aircraft.

Structural Testing

MERC’s specialized mechanical engineering capabilities include material strength testing and non-destructive evaluation subcategories. MERC’s structural test lab includes a 265,000-pound load frame, 110,000-pound load frame, and two 22,000-pound load frames for static and fatigue testing.

The 265,000-pound load frame can test up to 15 feet specimens. Using the 22,000-pound load frames, MERC performs coupon tests as well as fastener tests. Coupon testing capabilities include tests for elastic and shear modulus, shear, tensile and compressive strength on flat, round, or any other shape specimen. MERC has the ability to characterize composite layups and sandwich panels, including the constituent material properties using combinations of tensile, direct shear, and flexural beam tests to various ASTM standards.

MERC can perform crack growth (delta K vs. da/dN) fatigue and static coupon tests. For fatigue testing or durability testing, the load frames and control software allow for sinusoidal constant amplitude, sinusoidal loads of varying amplitudes, or spectra loading. MERC has the ability to use a second structural actuator to apply loads in a second direction to replicate real-life loading scenarios for either fatigue testing or static testing of large assemblies or components.

MERC has the experience to analyze test data and make correlations to finite element models or flight/road test data. MERC has NDI level III certified personnel in all five (5) NDI techniques who are available for inspections for both testing at MERC or for any on-site NDI needs.

MERC’s Structural Test Lab

Utilizing a 265 Kip load frame and a 110 Kip load frame, MERC can perform full-scale structural testing on very large components or assemblies.

MERC’s large-scale testing capabilities include:

  • Fatigue/dynamic test frequencies up to 20 Hz
  • Specimen sizes up to 15 feet
  • Specimen deflection of up to 6 inches
  • Static testing to +/- 265,000 lb.
  • Fatigue testing to +/- 220,000 lb.

MERC’s coupon and fastener test capabilities include:

  • Fatigue testing to +/- 20,000 lb.
  • Static testing to +/- 22,500 lb.
  • Specimen deflection of up to 10 inches
  • Specimen sizes up to 51.5 inches
  • Fatigue/dynamic test frequencies up to 60 Hz

Custom Test Development

MERC has the ability to meet any special testing needs. If your component or assembly is too large or of an awkward shape for one of our load frames, we can design and build a custom testing solution for your application.

MERC has onsite design, fabrication, and analysis capabilities for creating fixtures for everything from specialized coupon testing up to the testing of large components that see very high displacements.

Our structural actuator can be mounted anywhere in our lab and provides +/- 22,500 pounds of force and 10 inches of displacement with precision control over force and displacement. This flexibility allows MERC to test objects that are too large or too heavy to test otherwise. MERC can even install this actuator in a stationary vehicle to recreate internal loads in a structure or mechanism.

For more information, contact our team today.