Test device for acquiring plate thermoforming limit diagram

Abstract

The invention provides a test device for acquiring a plate thermoforming limit diagram. The device includes a universal tester, a mould, a strain measurement analysis apparatus, a heating control apparatus and a heat insulation apparatus. The universal tester includes a middle beam and a force sensor connected to the middle beam. The heating control apparatus consists of a temperature control unit and a heating component and a temperature sensing component that are respectively connected to the temperature control unit. The mould comprises a female die base, a blank-holding die and a male die. The female die base and the blank-holding die are assembled through a blank holding force control apparatus to form a plate clamping part for clamping plates. The strain measurement analysis apparatus consists of a controller, a metal corrosion marking unit and a CCD image sensor. The test device provided by the invention has a simplified overall structure, through combination of the universal tester, the mould, the strain measurement analysis apparatus, the heating control apparatus and the heat insulation apparatus, realizes precise control of the plate blank holding process and stamping forming process, and accurately acquires the plate thermoforming limit diagram.

Description

technical field [0001] The invention relates to the technical field of hot stamping forming devices for metal sheets, in particular to a testing device for obtaining hot forming limit diagrams of sheets. Background technique [0002] On the basis of ensuring the excellent mechanical properties of the material, the hot stamping forming process of metal sheet can effectively reduce energy consumption and environmental pollution, and realize lightweight production. However, due to the increasing requirements for production efficiency in modern society, it is very important to optimize the forming process and determine whether the material can be formed into qualified parts. In the forming process, the forming limit indicates the maximum forming capacity that can be achieved when the sheet metal is plastically formed. Therefore, accurate measurement of the forming limit of the metal is of great significance for making full use of the properties of the material, reducing producti...

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Problems solved by technology

[0003] Accurately obtaining the limit diagram of hot forming of sheet metal is more complicated, and there are many influencing factors. There are still many problems in the research of FLD. The research on the influence factors such as strain rate, blank holder force, limit state and loading temperature of FLD is still not mature enough.

Most of today's thermoforming limit experiments stop the experiment by directly observing the sample rupture or shrinkage to determine the forming limit, which may cause large manual errors, and even cause the test to fail, and a new experiment is required

[0004] Regarding the research on the above-mentioned influencing factors, the patent application No. 201310337979.7 mentioned a method and its testing device for obtaining the limit surface diagram of metal high-temperature warm forming, but the test method used can judge the instability behavior of the sheet metal. There is no uniform standard, and the strain is measured by photographing the compressed or ruptured specimen after the test

The patent application number 201410076641.5 mentions a method for establishing the hot forming limit diagram of high-strength steel plates. The high-speed camera is used to measure the stress change on the surface of the specimen at any time during the experiment, and the experiment is stopped by observing the rupture or contraction of the specimen in real time. There is no guarantee that the instability state of each sample is the same

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