JBM-Lb300H Microcomputer-Controlled Pendulum-Type Instrumented Force-Sensing Oscilloscope Impact Testing Machine

Product Introduction:

The JBM-Lb300H microcomputer-controlled pendulum-type instrumented impact testing machine features a high-rigidity frame, microcomputer control, and automatic measurement and recording of force‑time history. Its software is powerful, stable, reliable, highly accurate, and easy to operate. It is designed to evaluate the dynamic impact resistance of metallic materials and to assess their toughness–brittleness transition under dynamic loading. Equipped with an impact‑force sensor, it measures the load experienced by the specimen during the impact test, providing an accurate representation of the force‑time evolution throughout the test. The machine can assess the impact performance of metals at both room temperature and low temperatures, as well as determine the material’s toughness–brittleness transition temperature. It is widely applicable across research institutes, testing organizations, universities, and industries—including aerospace, defense, metallurgy, mechanical engineering, pressure vessel manufacturing, shipbuilding, automotive, bridge construction, and wind power—for precision material research, material analysis, material development, material selection, process optimization, and quality control.

Reference standard:

GB/T 2611 “General Technical Requirements for Testing Machines”

JB/T 7406.1 “Terminology for Testing Machines—Material Testing Machines”

GB/T 3808 “Verification of Pendulum Impact Testing Machines”

GB/T 229 “Method for Charpy Pendulum Impact Test of Metallic Materials”

JJG 145 “Pendulum Impact Testing Machine”

ISO 148:1998 "Metallic materials—Charpy pendulum impact test"

ASTM E23-07a “Standard Test Methods for Notched Bar Impact Testing of Metallic Materials”

GB/T 18658-2002 “Charpy V-notch Standard Specimens for the Verification of Pendulum Impact Testing Machines”

JB/T 6147—“Technical Requirements for Packaging, Packaging Marking, and Storage and Transportation of Testing Machines”

ISO 14556:2000 “Steel—Charpy V-notch pendulum impact test—Instrumented test method”

GB/T 19748 “Instrumented Test Method for Charpy V-Notch Pendulum Impact Testing of Metals”

JJF 1320 “Calibration Specification for Instrumented Charpy Pendulum Impact Testing Machines”

Technical Specifications:

Technical Features and Advantages:

1. The host frame and base are integrated in a single design and manufactured via monolithic casting, eliminating the weak joint between the body and base. This significantly enhances overall rigidity and stability, thereby improving test reliability. With reduced energy absorption by the machine itself, the measured results more closely reflect the specimen’s true absorbed energy, making it particularly well suited for high‑energy impact testing.

2. The integrated design eliminates assembly errors associated with the connection of separate‑piece frame bases.

3. The mainframe features a high-rigidity design; each load-bearing component is subjected to finite-element analysis and optimized in the design phase, followed by precision machining and rigorous testing.

4. The machining center performs one‑pass machining of the front and rear bearing bores and the anvil mounting locations, ensuring that the front and rear bearing bores are symmetrical and that the distance from the swing axis to the impact point is accurate.

5. The frame features a double-support structure, with the pendulum spindle supported by a simply supported beam, ensuring rational load distribution and reducing lateral oscillations of the pendulum during impact.

6. The front and rear bearings of the oscillating shaft experience balanced loading, reducing friction and minimizing impact‑induced damage to the bearings.

7. High-precision bearings with low friction, impact resistance, and long service life;

8. The rocker arm is made of thick-walled seamless tubing, offering high stiffness and resistance to deformation, thereby reducing energy absorption.

9. The pendulum’s circular hammer head is precisely designed using 3D software, ensuring an accurate center of gravity; its circular structure effectively reduces air resistance and minimizes energy loss during impact.

10. The impact blade is crafted from a specialized material, offering high hardness, minimal deformation, and excellent impact resistance.

11. The impact blade is available in two configurations—2 mm and 8 mm—and is secured via a screw‑tightening mechanism, making replacement simple and convenient.

12. Special materials and specialized machining are used to fabricate the specimen anvil (specimen support jaws), ensuring that the cutting edges are robust and smoothly rounded, with seamless transitions between flat surfaces and circular arcs, as well as excellent impact resistance and wear resistance.

13. A two-stage reduction motor is used as the hammer‑lifting drive, providing high torque, preventing slippage, and generating low noise. The reduction motor is manufactured using German technology, ensuring reliable performance and long-lasting durability.

14. The electromagnetic clutch, manufactured using advanced foreign technology, features rapid engagement and disengagement with no slippage.

15. The system employs a high-speed data acquisition module for operational control, automatically managing the entire testing process—including pendulum swing, pendulum suspension, impact, and pendulum release—ensuring reliable operation and significantly reducing the incidence of electrical faults.

16. The pendulum is controlled by a high-speed data acquisition system at a preset angle, ensuring precise positioning and stability to maintain a constant initial impact energy.

17. The pendulum‑hanging mechanism is equipped with a hydraulic cushioning system, ensuring smooth, vibration‑free operation and preventing impact and damage to the pendulum‑hanging/‑dropping mechanism.

18. Electrically driven decoupling impact, clean and precise, ensuring that the initial impact energy and initial velocity remain unaffected;

19. After the impact is completed, the remaining energy automatically re‑engages the pendulum, preparing it for the next strike and thereby improving operational efficiency.

20. The initial energy level can be adjusted by replacing the pendulum, thereby expanding the range of applications.

21. Operation can be performed via the microcomputer interface or through the touch screen;

22. By employing a high-precision optical encoder to accurately measure the angle and using a computer to calculate the impact absorption energy, the accuracy of impact energy measurement is significantly enhanced.

23. Two types of energy display: dial scale and microcomputer display;

24. The software design includes an automatic calibration function, enabling the measurement of frictional energy loss and aerodynamic drag energy loss.

25. Independent electrical control cabinet with complete separation of power and low-voltage circuits to minimize interference.

26. Equipped with a safety pin; once the pendulum reaches its preset position, the safety pin automatically disengages, preventing accidental dropping and potential accidents.

27. The entire machine is equipped with a split, modular, openable, fully enclosed protective cover featuring an aluminum alloy and tempered glass construction, ensuring both safety and aesthetic appeal.

Overall machine structure:

This testing machine comprises seven major components: the main frame, the low-temperature refrigeration system, the specimen chamber and sample‑feeding positioning system, the control system, the measurement and display system, the test fixtures, and the safety protection devices.

(1) Host Section:

It employs a large base and a wide, thick double‑support frame structure. The frame base is cast as a single piece, with the upper portion of the double‑supported frame integrally cast and connected; the reducer mounting bracket is also cast as part of the frame. The entire machine forms a rigid monolithic unit that, after natural aging followed by artificial aging, exhibits exceptionally high stability. With all components machined as a single unit and no assembly tolerances between the frame base and other parts, the distance from the pendulum axis to the impact center is ensured to be highly accurate. In conventional split‑type machines, bolted joints can undergo elastic deformation under impact, compromising measurement precision; the integrated design eliminates this issue entirely. The columns are symmetrically arranged front to back, and the pendulum spindle is supported in a simply supported beam configuration, effectively suppressing lateral vibrations during impact and minimizing their influence on test results.

(II) Operation Control System:

The system operates under program control, driven by a two-stage reducer and an electromagnetic clutch. During testing, the operator initiates the pendulum‑raising sequence via the microcomputer interface or the control panel: pressing the “raise” command engages the clutch and starts the reduction motor, which rotates the pendulum counter‑clockwise to lift it until it reaches the preset angle. At that point, an optoelectronic sensor sends a signal to stop the motor and disengage the clutch; the pendulum‑hanging mechanism then secures the pendulum’s hook, completing the preparation for impact. Pressing the “impact” button triggers the traction electromagnet to rapidly release the hook, allowing the pendulum to fall freely in a clockwise direction and strike the specimen. After the specimen fractures, the pendulum returns to its highest position in the forward direction using residual energy. The measurement and control system then commands the electromagnetic clutch to engage and the motor to start, driving the pendulum upward in a counterclockwise motion. Once the predetermined angle is reached, the motor stops, the clutch disengages, and the pendulum‑hanging mechanism re‑secures the pendulum’s hook, thus concluding one impact cycle and preparing for the next. Following the test, the fractured specimen falls onto a recovery conveyor belt. Based on pre‑set criteria,合格 (qualified) and不合格 (unqualified) specimens are routed to separate collection units. The system exhibits strong anti‑interference capabilities, ensures smooth operation, and delivers safe, reliable performance.

(3) Measurement Display System:

1. Dial display: After the impact is completed, the impact energy value can be read directly from the dial’s pointer.

2. Microcomputer‑based measurement, computation, and display: A high‑precision optical encoder is mounted at the end of the pendulum’s pivot axis to accurately measure both the lifting angle of the pendulum and its rebound angle after impact. The system automatically identifies these angles, with the number of output electrical pulses being directly proportional to the lifting or rebound angle. The microcomputer processes the signals and performs calculations to determine the precise impact energy value.

3. The software features an automatic calibration function, enabling the measurement of bearing friction energy loss, pointer friction energy loss, and air‑resistance energy loss. It can automatically subtract pre‑existing friction and air‑resistance losses from the calculation results, thereby enhancing the accuracy of the test outcomes.

(3) Measurement Display System:

1. System Block Diagram

The system comprises an impact force sensor, an encoder, a dynamic force transducer, a data acquisition unit, a data analysis system, a computer, and a printer, among other components.

2. Description of Each Component’s Functions

◆ Impact sensor:

The impact force sensor is specially designed to meet specific requirements, enabling the measurement of the forces experienced by a specimen during an impact event and accurately capturing the temporal evolution of these forces.

◆ Encoder:

The encoder is used to measure and control the pendulum’s release height and to determine the rebound angle during the impact test. It is mounted on the pendulum’s pivot axis, and the number of output electrical pulses is proportional to the pendulum’s release or rebound angle.

◆ Dynamic force transducer:

The dynamic force transducer primarily supplies power to the impact‑force sensor and the encoder, preprocesses the output signals from both sensors, outputs standard electrical signals to the data acquisition system, and generates control signals for the control cabinet.

◆ Data Acquisition Card:

The data acquisition card’s function is to capture the required data with a sufficiently high sampling rate, perform analog-to-digital conversion, and feed the data into the computer. At the same time, it outputs control signals to the control cabinet.

◆ Calculation and Control Software:

This software is specialized and, through computational analysis, provides 24 quantitative parameters, including the pendulum’s impact velocity, impact energy, absorbed energy, crack‑initiation energy, crack‑propagation energy, yield force, yield energy, yield time, yield displacement, maximum force, energy at maximum force, time at maximum force, displacement at maximum force, the onset force for unstable crack propagation, the onset energy for unstable crack propagation, the onset time for unstable crack propagation, the termination force for unstable crack propagation, and the termination time for unstable crack propagation. It also generates test reports automatically and uses control signals to manage the pendulum’s raising, impact, releasing, and stopping operations.

3. Main Functions

1) Measurement of the pendulum’s swing angle and rebound angle: A high-precision encoder is used to measure the pendulum’s swing angle and rebound angle, enabling automatic identification of the swing angle for variable‑angle pendulums. The angular measurement accuracy reaches ±0.1°, with an angular resolution of 0.025°.

2) Measurement of the force–time waveform during impact testing: An impact force sensor specially developed for pendulum impact testers is used to measure the force–time waveform experienced by the specimen throughout the pendulum impact test.

3) Data Acquisition: A high-performance, high-sampling-rate data acquisition card imported from abroad is used to capture the force–time waveform experienced by the pendulum during the impact event, ensuring a sufficient number of sampling points over the very brief impact duration and thereby guaranteeing the accuracy of the energy‑change curve.

4) Software Analysis: The test system is equipped with robust software analysis capabilities, meeting users’ data-processing requirements and delivering the corresponding results.

5) Control Functions: The system can generate multiple-level signals to control various functions of the pendulum, including raising, releasing, retracting the pin, and impact, enabling fully software‑based operation.

6) Air‑free calibration: A high‑precision encoder is used to continuously measure the frictional and aerodynamic losses of the testing machine and automatically compensates for them in the test results, thereby enhancing measurement accuracy.

7) Automatic determination of invalid tests: For dead‑drop tests, if the energy absorbed by the specimen is less than 10% or greater than 90% of the maximum impact energy, the test is deemed invalid; the software automatically detects this and provides an alert.

8) Test results show that, through software analysis, the following parameters can be displayed for this test: impact angle, impact energy, absorbed energy, impact velocity, impact duration, maximum force, energy at the time of maximum force, deformation at the time of maximum force, yield force, time to yield, deformation at the time of yield, buckling force, time to buckling, deformation at the time of buckling, force–time waveform, force–displacement waveform, and energy–time waveform; furthermore, these results can be printed out via a printer.

9) Report Generation: After each test is completed, a test report is automatically generated, containing the eight test results as well as relevant information such as specimen dimensions, grade, identification number, temperature, and ambient temperature and humidity. The report can be saved and retrieved for easy access. All reports are generated automatically (except for the percentage of shear area), so no manual input is required by the user.

10) Database Functionality: Key data such as impact energy, absorbed energy, and impact velocity can be saved to the same Excel file via a single button on the main interface. Each test is recorded on a separate row, with data arranged sequentially, facilitating easier storage, retrieval, and comparison.

11) Cursor Readings: Data on the waveform can be directly read using the measurement cursor.

12) Periodic Measurement: Automatically determines the pendulum’s oscillation period, calculating the average period after 100 oscillations within a swing amplitude of less than 5°.

13) Energy Loss Test: Automatically measures the air and mechanical friction losses of the pendulum over ten half-periods.

14) Swing‑out prevention: In the event of operator error or a malfunction of the testing machine, the pendulum may swing with a large amplitude. If the pendulum needs to be stopped at this point, it must either be manually halted or allowed to come to rest over an extended period. Manual stopping poses safety risks; therefore, a swing‑out prevention mechanism is provided to enable the pendulum to be locked in place while it is swinging.

15) The aforementioned curves and individual energy values can also be easily copied into a Word document, allowing users to generate test reports that meet their requirements.

16) Operation: The software employs a sequential operation mode. Corresponding dialog boxes will appear one after another on the interface, and the next step cannot be initiated until the previous operation is completed, thereby helping to prevent unexpected issues.

Through data analysis and software processing, the microcomputer can generate curves such as force–time, displacement–time, energy–time, force–displacement, and energy–displacement.

Test Data and Test Report:

Through data analysis and computation, the software can derive multiple characteristic parameters, including: impact velocity, impact duration, impact energy, absorbed energy, displacement, crack‑initiation energy, crack‑propagation energy, yield force, yield time, yield displacement, yield energy, maximum force, time at maximum force, displacement at maximum force, energy at maximum force, the onset force for unstable crack propagation, the termination force for unstable crack propagation, the termination displacement for unstable crack propagation, as well as the onset energy and termination energy of unstable crack propagation.

Safety protection device:

The testing machine is designed with safety of use and ease of maintenance firmly in mind.

(1) Safety device: A safety pin is installed at the position where the pendulum passes during its descent. When the pendulum rises to the preset position, the safety pin automatically extends, preventing the pendulum from falling and causing an accident in the event of a hanging‑pendulum malfunction. During impact, the safety pin must first be retracted before the impact can be initiated, thereby avoiding accidental injury due to operator error.

(2) Safety Guard: Equipped with a fully enclosed, transparent front guard, it effectively prevents fragments of broken specimens from flying out and causing injury, while also keeping personnel from entering the test area during operation. The guard features a door limit switch: when the protective door is open, the testing machine automatically cuts power and locks itself, rendering all primary controls inoperative, thereby preventing accidental misoperation and ensuring operator safety. The guard is a modular, hinged design that facilitates maintenance, repair, and pendulum replacement. It consists of an aluminum alloy frame and tempered glass, offering both robustness and an aesthetically pleasing appearance.