RS Technologies


	SR1 Bolted Joint Design & Analysis

Data Outputs

Data Outputs
Once the bolted joint has been thoroughly specified, you can obtain any of the numerous charts graphs and printouts provided by SR1.

Safety Factors
Perhaps, the most important output of SR1 are the safety factor evaluations for thread strip, embedment, bolt stretch, etc. A careful review of the safety factors will reveal the presence of any critical flaws in the assembly.

M-Alpha and F-Alpha Diagrams
Two of the most important enhancements to the VDI standard, provided by SR1, are the M-Alpha (torque vs. angle) and F-Alpha (clamp force vs. angle) diagrams. These show torque or clamping force as a function of angle of turn starting at the elastic origin. The elastic origin is located by projecting the tangent of the tightening curve at the preload point back to the starting torque level. The location of the elastic origin is important because the tension of the joint is directly proportional to the angle of turn from that point. Correlation of the M-Alpha and F-Alpha diagrams allows estimations of joint integrity. These diagrams also present summary information for the joint. This includes fastener size and grade, friction coefficients, and calculated values for K based on input from friction coefficients and thread pitch. Also presented are critical safety factors for key design considerations such as thread strip and underhead embedment.

NOTE
The M-Alpha and F-Alpha diagrams have been included with SR1 to provide a link to the powerful torque-angle signature analysis methods developed by RS Technologies, Ltd. They can be correlated to comparable diagrams provided by fastener test equipment such as the Model 9504 LabMaster. They add major practical elements to the already powerful tools of the VDI 2230 analysis.

Load Extension Diagram
After the calculations are complete, you can display or print load extension diagrams for either assembly or working status. These diagrams illustrate the stretch of the bolt and the compression of the parts being clamped. The spring rate and stiffness of the clamped parts is estimated by up to 10 user-definable cylinders or disks that simulate the geometry of the joint.

Printouts
After all elastic compliances, forces, loads, and tightening moments are calculated, all data can be displayed on-screen, sent to a printer, or saved.

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