Fixing Armor Rods Grip Strength Stalling at 90 Percent Under GB/T 2317.1 Rules

Tensile Load Verification Under GB/T 2317.1

A grip threshold stalling at 90 percent occurs when inner radial pressure fails before reaching target Rated Tensile Strength. Proper assembly requires matched lay direction, verified conductor diameter, and intact abrasive grit coating to prevent premature strand slip during tension verification.

Standard test procedures demand that every armor rod preformed set sustains ninety-five percent conductor rated strength without slippage. When displacement occurs below this parameter, mechanical friction along outer aluminum layers cannot transfer tensile force into the internal steel core.

Primary Causes for Mechanical Grip Slippage

Conductor and Fitting Alignment

1. Substrate Diameter Tolerance: Variations in conductor circumference reduce radial clamping force. Installing armor rods for acsr on undersized stranding creates uneven contact, which triggers premature core slippage during high-load pulling phases inside the universal testing frame.

2. Surface Grit Quality: Carborundum particles bonded inside each leg must bite through oxide films. Worn adhesive allows internal particles to shear under eighty-five percent tension, causing catastrophic grip loss before achieving target test certification values.

Correcting GB/T 2317.1 Laboratory Parameters

Machine Setup and Clamp Calibration

Tensile machine grips frequently introduce artificial bending moments. Securing each preformed armour rod assembly requires free-clevis end fittings with sufficient gauge length. Fixed rigid chucks introduce bending stresses that peel protective aluminum wires away from the main tension axis.

1. Loading Velocity Regulation: GB/T 2317.1 specifies steady loading rates below specific crosshead speeds. Accelerating pull rates causes shock loading, which shears outer contact surfaces and drops effective holding capacity below standard compliance levels during laboratory examination.

2. Span Length Selection: Insufficient free cable length between termination clamps distorts radial compression profiles. Maintaining recommended spans guarantees balanced stress distribution along the full contact area of armor rods during tensioning cycles.

Mechanical Inspection Matrix for Holding Tests