Standard Test Method for Pin-Bearing Testing of Metallic Materials
APP-E238Measure both the pin outer diameter and hole inner diameter to the nearest 0.01mm to document exact clearance values.
Challenge & Testing Gap
Localized material yielding and pin deformation introduce extraneous structural displacement, masking true bearing yield strength.
The Solution
Deploy a dedicated dual-extensometer assembly clamped directly onto the specimen edge flanking the loading pin.
Mechanics & Specimen Behavior
Primary Mechanics
Compressive force applied by a hardened cylindrical pin through a matching close-tolerance hole in a sheet or plate specimen.
Specimen Details
Flat rectangular coupon containing a precision-machined or reamed pin-hole near one edge.
Mechanical Ratios & Properties
Edge-distance-to-diameter ratio (e/D) typically configured to fixed baselines of 1.5 or 2.0.
Expert Engineering Commentary
Core Problem Identification
Elongation or ovalization of the hole structure before ultimate bulk tensile or shear edge breakout.
Root Cause Analysis
Pin bending or micro-clearance gap slippage within the load frame coupling causing non-linear initial loading artifacts.
Hardware Specific Solutions
Hardened tool steel clevis fixture with matched precision ground loading pins and automatic self-centering pull rods.
Analysis & Calculation Standards
Event & Failure Detection
0.2% or 2.0% offset bearing diameter deformation event tracking.
Required Calculations
Bearing Yield Strength, Ultimate Bearing Strength, Bearing Stress-Strain Curves, and Hole Elongation Metrics.
Statistical Outputs
Mean bearing limits, offset displacement variations, and standard deviations across a minimum 3-specimen set.
Continuous digital data filtering using moving-average algorithms to separate pin seating artifacts from true structural elastic deformation.
Additional Commentary
Proper clevis-to-pin clearance ensures pure bearing stress distribution without edge jamming.
Use hardened pins exclusively; soft steel pins will bend elastically and introduce invalid displacement signals.
Common Pitfalls
Calculating displacement from total crosshead travel instead of direct-on-sample extensometers.