Pagnotta Engineering, Inc.

JOINT ANALYSIS

Mechanical, welded, and bonded connections

MECHANICAL CONNECTIONS:
Mechanical connections generally refer to joints that utilize interfering hardware, such as bolts, rivets, and pins. Pagnotta Engineering uses
custom designed software based on industry and government accepted methods to analyze mechanical connections.

EXAMPLE PROJECT:
CH-53 Visual Upgrade

CUSTOMER:
Binghamton Simulator Company

SERVICES PERFORMED:
• The CH-53 flight simulator visual support structure includes a projector platform and supporting leg structures
• The legs are attached to the projector platform members using splice plates and bolts
• Loads from the leg members used to calculate splice plate loads and individual bolt loads
• Splice plate, bolt and local stresses in connecting members assessed to show sufficient design margin of safety


FEM of platform and legs	Pro/E Model	Detailed Connection

EXAMPLE PROJECT:
TH-57 Visual Upgrade

CUSTOMER:
Rockwell-Collins STS

SERVICES PERFORMED:
• Developed system FE model of TH-57 simulator structure
• Developed detailed FE model of the more complicated connection details to automade the analysis process
• Gross stress levels of joining members assessed
• Loads at connection elements extracted so that bolt and weld stresses can be analyzed


FEM of joint	Stress contour of joint

WELDED CONNECTIONS:
Welding is a cost effective and structurally efficient way to create assemblies consisting of common materials. Pagnotta Engineering uses
industry and government accepted methods to analyze welded connections. Depending on the specific nature of the welded connection,
either direct ("on-the-screen") or indirect (model for loads, weld assessment by "hand-analysis") methods may be employed.

DIRECT MODELING METHODS

EXAMPLE PROJECT:
Stress Analysis of Medical
Implant Enclosure

CUSTOMER:
HI-TRONICS Designs, Inc.

SERVICES PERFORMED:
• Detailed FE model of the implant enclosure developed
• Plate stresses at the welded titanium seam determined and compared to allowable stress levels


Stress contour	Close-up of weld seam

INDIRECT MODELING METHODS

EXAMPLE PROJECT:
Analysis of Electronics Rack
Support Frame

CUSTOMER:
Rockwell-Collins STS

SERVICES PERFORMED:
• Electronics Rack Support Frame FE model created using beam and plate elements
• Beam and plate loads extracted from FE model
• Welds assessed by hand using classical hand analysis methods


Rendered FE model	Pro/E CAD model

BONDED CONNECTIONS:
Bonded connections offer a light weight efficient connection and are a solution when good manufacturing process control is established.

EXAMPLE PROJECT:
DAWN CSS Tube Assembly

CUSTOMER:
Orbital Sciences Corp.

SERVICES PERFORMED:
• Built detailed FE model of GRP post and metallic base fitting, including elements representing the
adhesive material
• Ran thermal soak to determine stress levels in the adhesive and the joining parts
• Stresses develop due to differences in the termal expansion coefficients of the materials
• Failure loads were determined