JPH0465652A - Toughness value measuring method and tensile impact testing machine for touchness value measurement - Google Patents

Abstract

PURPOSE:To reduce the size by regarding the absorption energy of a shock tension test for unit volume of a material as a toughness value by paying attention to the fact that the absorption energy of a high-speed tension test for a material is almost in proportion to its volume. CONSTITUTION:For the toughness value measurement, when a mass body is accelerated to tense and break a test-piece with its speed energy, the massive body 1 is placed in a free flying state right before being loaded and the energy required to break the test-piece 2 is measured from the speed right before the loading and regarded as the toughness value. On the tensile shock testing machine for toughness value measurement, the test-piece 2 is supported at its one end on a frame by a gripper and the other end receives a tension load by the gripper; and the massive body 1 is pressed up by a pressing-up device 7 against an acceleration device until it is caught by a hacker device 10 and the test is started by disengaging the hacker 9. Then the mass body is accelerated by the acceleration device, an acceleration stop ring 11 abuts on an acceleration stop seat 12 right before the test-piece 2 is loaded, and the massive body 1 enters the free flying state after this point of time to tense and break the test-piece 2.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for measuring absorbed energy per unit volume (hereinafter referred to as toughness value) required for tensile rupture of a material (test specimen) and toughness value measurement. Concerning a bow string impact tester.

[Prior Art] Some conventional tensile impact rupture testers use the acceleration of gravity to obtain the velocity of a mass body, but in order to obtain a high velocity, the drop is high and the machine is large.

In addition, there is no device that accelerates the mass body using an accelerator, which adds acceleration even during loading of the test piece, and can accurately measure the absorbed energy from the difference in speed of the mass body.

There is no indication of the absorbed energy per volume of the test section of the test piece.

[Problem to be solved by the invention] There are few conventional impact testers that directly utilize tensile loads; Charpy type, Izod type, etc. break the test piece by bending, and the measured values are basically displayed in a manner specific to that method. Unit (C
, G, S, or SI units).

In the present invention, the toughness value per unit volume can be expressed in basic units.

In international units (SI units), absorbed energy can be expressed as N: newton (force) m: meter (length).

[Means for solving the problem] The toughness value measurement method focuses on the fact that the absorbed energy of a substance in a high-speed tensile test is approximately proportional to its volume, and calculates the absorbed energy of a unit volume of a substance in an impact tensile test. Let be the toughness value.

The toughness measurement method involves accelerating a mass body and using its velocity energy to tensilely break the test piece.The mass body is placed in a free flight state immediately before loading, and the energy required to break the test piece is calculated using the velocity just before loading. Measure and use this as the toughness value.

In the tensile impact tester for measuring toughness, the test piece is supported by a frame with a grip at one end, the other end is subjected to a tensile load by the grip, and the mass is applied to a hacker device by a push-up device against an accelerator. The test is started by releasing the hacker, the mass is accelerated by the accelerator, and the acceleration stop ring hits the acceleration stop pressure just before it is loaded onto the test piece, and the mass does not move from this point onwards. It was characterized by tensile fracture of the specimen in a free flight state.

[After accelerating the acting mass to a predetermined speed, put it in free flight,
Measure its speed. Next, after the test piece is fractured by the velocity energy of the mass, the velocity of the mass is measured. Calculate the absorbed energy required to break the test piece by comparing both speeds.

[Example] (1) Test-related part 2a of tensile absorption energy of test piece 2
Let the volume of be the unit volume.

The most commonly used dimensions are 0.5 cm2 in cross section and 2 cm in length, and the effective volume is ICW13.

(2) As the main body of the test machine, the mass body 1 is pushed up by the mass body push-up device 6.7 against the spring 8 of the accelerator device until it is caught on the hacker claw 9 of the hacker device 10, and thereafter the push-up device 7 returns to its original position. Return until.

When the hacker device 10 fixed to the frame 5 is released, the mass l is accelerated by the energy retained in the accelerator 8.

The mass body 1 is accelerated until the acceleration stop ring 11 fitted to the mass body 1 hits the acceleration stop pressure 12 of the frame, and thereafter the mass body 1 is in a free flight state.

Immediately before the mass 1 hits the jaw 16 of the specimen gripper 4, the speed 1 of the mass 1 is measured by the speed detector 14. 13 is a detection end for speed measurement.

An impact load is applied to the test piece 2 by the test piece gripper 4, and the test piece 2 stretches and breaks. Immediately after the rupture, the velocity v2 of the mass body 1 is measured by the velocity detector 15.

Thereafter, the mass body 1 is decelerated and stopped by the damper device 17.

18 is a damper hydraulic chamber.

(3) In the above process, the following formula holds true according to the energy principle.

Ei+Ed=Ea+Er El: Energy received by the mass body by the accelerator Ed: Potential energy given to the mass body by the head difference between speed detectors 14 and 15 (zero in horizontal format) Ea: Energy absorbed by the test piece Er: Residual energy of the mass body at the position of the speed detector 15 E d = d m g m: Mass of the mass body ■,: Velocity at the position of the speed detector 14 d: Head difference between the speed detectors 14 and 15 g: Gravity acceleration (approximately 980 m/sec2) Therefore, Ea = Ei + Ed - Er Since Ed is a constant value depending on the type of testing machine, the absorbed energy Ea can be accurately calculated by measuring V and v2.

Furthermore, it is obvious that the tensile fracture absorption energy of a test piece in homogeneous materials is proportional to its length if it has the same cross-sectional area, and is proportional to its cross-sectional stone if it has the same length. The absorbed energy is approximately proportional to the effective volume of the specimen.

Therefore, various effects can be achieved, such as being able to display the toughness value per unit volume in basic units.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of a tensile impact tester for measuring toughness, and FIG. 2 is a front view of a test piece. DESCRIPTION OF SYMBOLS 1... Mass body, 2... Test piece, 3, 4-... Test piece gripping tool, 5... Frame, 6, 7... Mass body pushing device, 8... Spring, 9... ... Hacker claw, 10 ... Hacker device, 11 ... Acceleration stop ring, 12 ... Acceleration stop dust, 13 ... Speed measurement detection end, 14.15 ...
Speed detector, 16... Jaw, 17... Damper device, 18... Damper hydraulic chamber. can be considered as the eigenvalue (characteristic value) of the material. [Effect of the invention]

Claims (1)

[Claims] [1] Focusing on the fact that in a high-speed tensile test of a material, the energy absorbed by the material is approximately proportional to its volume, toughness is defined as the absorbed energy in an impact tensile test of a unit volume of the material as the toughness value. Value measurement method. [2] When accelerating the mass body (1) and tensilely breaking the test piece (2) with its velocity energy, the mass body (1)
is in free flight just before loading, and the velocity just before loading (v_
1) A toughness value measurement method in which the energy required to break a test piece is measured and this is taken as the toughness value. [3] The test piece (2) is supported at one end by the frame (5) by the gripper (3), the other end is subjected to a tensile load by the gripper (4), and the mass body (1) is supported by the push-up device (6, 7), the mass body (1) is pushed up against the accelerator (8) until it hangs over the hacker device (9), and the test is started by releasing the hacker (9), and the mass body (1) is pushed up against the accelerator (8). The acceleration stop ring (
11) hits the acceleration stop seat (12), and after this point the mass body (1) enters a free flight state to perform tensile fracture of the test piece (2).