0
Research Papers

An Empirical Relationship for Extrapolating Sparse Experimental Lap Joint Data

[+] Author and Article Information
Michael J. Starr

Daniel J. Segalman

 Sandia National Laboratories, P. O. Box 5800, Albuquerque, NM 87185-0346

J. Appl. Mech 78(6), 061002 (Aug 22, 2011) (8 pages) doi:10.1115/1.4003769 History: Received January 28, 2010; Revised March 03, 2010; Accepted March 08, 2011; Published August 22, 2011; Online August 22, 2011

Correctly incorporating the influence of mechanical joints in built-up mechanical systems is a critical element for model development for structural dynamics predictions. Quality experimental data are often difficult to obtain and is rarely sufficient to determine fully parameters for relevant mathematical models. On the other hand, fine-mesh finite element (FMFE) modeling facilitates innumerable numerical experiments at modest cost. Detailed FMFE analysis of built-up structures with frictional interfaces reproduces trends among problem parameters found experimentally, but there are qualitative differences. Those differences are currently ascribed to the very approximate nature of the friction model available in most finite element codes. Though numerical simulations are insufficient to produce qualitatively correct behavior of joints, some relations, developed here through observations of a multitude of numerical experiments, suggest interesting relationships among joint properties measured under different loading conditions. These relationships can be generalized into forms consistent with data from physical experiments. One such relationship, developed here, expresses the rate of energy dissipation per cycle within the joint under various combinations of extensional and clamping load in terms of dissipation under other load conditions. The use of this relationship—though not exact—is demonstrated for the purpose of extrapolating a representative set of experimental data to span the range of variability observed from real data.

Copyright © 2011 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

The simple, flat lap joint investigated here

Grahic Jump Location
Figure 2

BMD, with instrumented cable to apply preload to lap joint

Grahic Jump Location
Figure 3

Experimental values of energy dissipation per cycle

Grahic Jump Location
Figure 4

Bolted lap joints (color curves) and unjointed, monolithic (black curves) specimen dissipation

Grahic Jump Location
Figure 5

Numerical dissipation per cycle predictions for N = 1600 lb

Grahic Jump Location
Figure 6

An observation from finite element simulations of a lap joint is that for constant ψ=P/(μN), the dissipation per cycle has a power-law dependence on force amplitude of slope m on the order of m≈2

Grahic Jump Location
Figure 7

The Ψ-relationship is employed to map the power-law dissipation relationship that exists at clamping load N1 to that which exists at N2

Grahic Jump Location
Figure 8

Curve fits to numerical calculations (dashed lines) and extrapolations (solid lines) from the two filled data points. Symbols are data from discrete numerical calculations. N0=1200 lb and μ0=0.30.

Grahic Jump Location
Figure 9

Curve fits to numerical calculations (dashed lines) and extrapolations (solid lines) from the two filled data points. Symbols are data from discrete numerical calculations. N0=1200 lb and μ0=0.50.

Grahic Jump Location
Figure 10

Curve fits to numerical calculations (dashed lines) and extrapolations (solid lines) from the two filled data points. Symbols are data from discrete numerical calculations. N0=1200 lb and μ0=0.70.

Grahic Jump Location
Figure 11

Comparison of experimental data and numerical predictions for N=800 lb

Grahic Jump Location
Figure 12

Comparison of experimental data and numerical predictions for N=1200 lb

Grahic Jump Location
Figure 13

Comparison of experimental data and numerical predictions for N=1600 =lb

Grahic Jump Location
Figure 14

Families of constant ψ for assembly 1B, m¯=1.346

Grahic Jump Location
Figure 15

Families of constant ψ for assembly 2B, m¯=0.511

Grahic Jump Location
Figure 16

Extrapolation of experimental data using N0=1200 lb. The markers are experimental data, the red lines are fits to the experimental data at N=1200 =lb, and the black and green lines are curve fits to extrapolated predictions.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In