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Steel strand fatigue dynamic testing machine

Steel strand fatigue dynamic testing machine

Model: HDS, 50KN/100KN, ISO 15630-3, ASTM A416

ISO 15630-3, ASTM A416 Steel strand fatigue dynamic testing machine, high-cycle fatigue test 

Steel Strand Fatigue Dynamic Testing Machine is a specialized electromechanical testing system designed to evaluate the fatigue performance of prestressed steel strands under cyclic loading conditions. This advanced testing equipment combines hydraulic servo technology with precision control systems to simulate real-world stress conditions that steel strands experience in structural applications.


General introduction

ISO 15630-3, ASTM A416 Steel strand fatigue dynamic testing machine, high-cycle fatigue test 

The Steel Strand Fatigue Dynamic Testing Machine is a specialized electromechanical testing system designed to evaluate the fatigue performance of prestressed steel strands under cyclic loading conditions. This advanced testing equipment combines hydraulic servo technology with precision control systems to simulate real-world stress conditions that steel strands experience in structural applications.


Core Components:
Hydraulic servo loading system: Provides stable cyclic tensile forces up to 100 ~ 1,000kN
High-rigidity frame structure: Four-column design to minimize deformation during testing
Specialized clamping mechanism: Ensures secure grip without damaging the strand surface
Precision measurement system: Load cells, displacement sensors, and extensometers
Digital control console: PC-based with touchscreen interface for test parameter programming
Data acquisition system: Records and analyzes force, displacement, and cycle data in real-time. 

Key Features

  • Actuator:
  • Main Function:
  • Advanced Servo Control Technology
  • Specialized Fixture Design
  • Comprehensive Data Management
  • Robust Structural Design
  • Standards Compliance

The servo linear actuator is the core component of the testing machine, and the testing machine outputs test forces through the actuator. It is designed and manufactured using proprietary technology, with the actuator embedded in the lower part of the host machine, comprising the actuator body, hydraulic control module, and sensors.


1, The actuator uses our company's servo linear actuator, designed based on the principle of a symmetric four-way servo valve controlling a symmetric actuator. The actuator is designed and manufactured with a modular, standardized development concept, utilizing a multi-stage flexible support combination guiding mechanism, characterized by low damping, high responsiveness, long lifespan, and large clearance design. The startup pressure is less than 0.05 MPa, and there is no crawling phenomenon.

2, The piston seal of the actuator adopts a Glide ring guide and seal method, while the piston rod seal uses a Star seal guide and dust seal method. All sealing components are imported high-speed sealing elements specifically for servo actuators from Germany's Busak Shamban. The support of the piston rod of the servo linear actuator breaks from traditional design, using non-metal support, large clearance design, and high lateral force resistance, featuring high speed and non-sintering self-lubrication. The assembly achieves no oil leakage with combined seals for high-pressure sealing, low-pressure sealing, and leakage through clearance pipes. The combined sealing structure has good interchangeability, facilitating maintenance. It exhibits high speed, non-sintering, and self-lubricating characteristics. The above sealing methods effectively reduce the internal frictional resistance of the actuator, improving the testing accuracy of the machine and the lifespan of the actuator. The frequency response of the servo linear actuator is not less than 100 Hz.

1, Fatigue working life study;
2, Cracking extension and breaking load study;
3, Tensile, compression, bending cyclic test;
4, Components and parts fatigue and life working test.

Closed-loop control with seamless switching between load, displacement, and strain control modes
Frequency range: 0.01-50Hz (standard), with high-end models reaching 200Hz.
Position control accuracy: ±0.01mm.
Force control precision: ±0.5% of full scale.
Sinusoidal, triangular, and square wave loading patterns.

Patented strand clamping technology: Distributes pressure evenly to prevent damage
Self-aligning grips: Ensure axial loading to eliminate bending stresses
Interchangeable jaw inserts: Accommodate various strand diameters (from 6mm to 160mm)
Break location control: Designed to ensure specimen fractures in the middle for accurate strength measurement.

Real-time plotting of force-displacement, force-cycle curves
Automatic calculation of fatigue life, S-N curves, and other key parameters
Data storage capacity for 10,000+ test cycles with 0.1ms sampling intervals
Report generation in multiple formats (PDF, Excel, Word) with customizable templates.

Heavy-duty welded frame with stress-relief treatment
Horizontal/vertical configuration options for different testing requirements
Temperature compensation system to maintain accuracy during extended testing
Safety enclosure with interlocks to protect operators during high-load testing. 

ISO 15630-3 Conformance
This machine fully complies with ISO 15630-3:2019 "Steel for the reinforcement and prestressing of concrete — Test methods — Part 3: Prestressing steel" , meeting all requirements for:
Axial load fatigue testing: Applies sinusoidal tensile forces in the elastic range
Test frequency: Maximum 20Hz for 2 million cycles without failure
Load range: 40-80% of the specified tensile strength
Deflection testing: Determines force reduction coefficient after 20° deviation around a mandrel

ASTM A416 Conformance
The machine satisfies all testing requirements of ASTM A416/A416M-24 "Standard Specification for Low-Relaxation, Seven-Wire Steel Strand for Prestressed Concrete" :
Verifies minimum tensile strength for Grade 250 (1725MPa) and Grade 270 (1860MPa) strands
Tests yield strength according to ASTM A1061 protocol
Evaluates stress relaxation properties over 1000+ hours
Confirms strand elongation meets specified criteria


Additional Compliance
GB/T 5224 (Chinese standard for prestressed steel strand)
EN 10138 (European standard for prestressing steel)
ISO 6934 (International standard for prestressing concrete steel)

Main technical specification

Max. static load±200KN/500KN/1000KN, full range stepless, Accuracy ±1%
Max. dynamic load±200kN/500KN
Dynamic fluctuationLess than ±2%FS
Actuator max. stroke±75mm
Frequency0.01~50Hz
Max. speed700mm/s(21Mpa,70L/min)
Motor power30Kw
Controller typeSingle channel; displacement and load close-loop dual channels
Main test waveformSine wave, triangular wave, rectangle wave, oblique wave etc.
Test space750mm
Test width530mm
Round specimen clamping rangeφ6~φ25mm
Flat specimen clamping range0-26mm
Weight of oil source750kg

Main accessories (Standard delivery with machine)

High Stiffness Frame1 set
Constant pressure servo oil source1 set
Hydraulic clamper1 set
Servo controller1 set
Fluid part connection1 set
Accessories1 set
Consumable parts1 set
Computer1 set
Printer1 set
Documents (Manual, packing list, certificate)


Advantages

1 Superior Testing Precision
Eliminates human error through fully automated testing processes
Consistent results with coefficient of variation (COV) typically <1%
Capable of detecting minute changes in strand behavior during fatigue progression

2 Increased Testing Efficiency
Reduces testing time by 50% compared to traditional methods
Can perform 2 million cycles (standard fatigue test) in approximately 28 hours
Automatic cycle counting with target completion shutdown
Parallel testing capability on some models for multiple specimens

3 Versatile Testing Capabilities
Performs not only fatigue tests but also static tensile, creep, and relaxation tests
Adapts to various standards (ISO, ASTM, GB/T) with simple software configuration
Test different strand types: low-relaxation, stress-relieved, galvanized, and composite strands

4 Long-term Reliability
Industrial-grade components with MTBF (mean time between failures) >10,000 hours
Low maintenance design with easily accessible hydraulic filters and seals
Energy-efficient operation (some models consume 70% less power than older designs)

Require More Customized Solutions?

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Beijing United Test Co., Ltd.