Vertical double-shaft four-cylinder electro-hydraulic servo testing machine

Abstract

The vertical dual-shaft four-cylinder electrohydraulic servo testing machine comprises: a hydraulic pressure drive for dual-direction stress filed, a four-cylinder drive fit to any loading path, a differential close-loop servo system, a function generator fit to different waves, a position transfer device fit to assemble the test piece, a guide plate and linear rail to ensure co-shaft and avoid bending. This invention is very convenient.

Description

technical field [0001] The invention relates to a vertical two-axis four-cylinder electro-hydraulic servo testing machine, which belongs to the technical fields of engineering materials, physical properties, structural deformation and mechanical experiments. It can be used to test the mechanical properties of materials, especially anisotropic composite materials, under biaxial tensile, compressive and fatigue loads. Background technique [0002] With the increasing application of lightweight composite materials in various industrial fields, it is urgent to complete the mechanical experiments of anisotropic materials under biaxial tensile, compressive and fatigue loads. This is because from the point of view of practical applications, composite materials generally bear loads in multiple directions; and from the anisotropy theory of materials, the stress distribution of materials is also very complicated under multi-bearing loading conditions. The traditional uniaxial Mechani...

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Problems solved by technology

This is because from the point of view of practical applications, composite materials generally bear loads in multiple directions; and from the anisotropy theory of materials, the stress distribution of materials is also very complicated under multi-bearing loading conditions. The traditional uniaxial Mechanical experiments cannot adequately provide the material properties and experimental data required for the effective application of anisotropic materials

[0003] At present, there are many kinds of biaxial testing machines at home and abroad. From the perspective of the realization of the bidirectional load field, there are mainly two methods: one is to create a bidirectional stress field inside the material through the combined tension and torsion loading of the thin-walled cylinder (Experimental mechanics, 23, 384-392, 1983), this method is relatively simple, but the loading path is limited, and it is an approximate two-way stress field, and cannot be applied to sheet materials; another method is to directly realize the two-way stress field

In terms of the drive system that directly realizes the two-way stress field, there are generally three methods: one is to realize the drive through a weight and a lever system (J.Strain Analysis, 8(2), 119-123, 1973) , this kind of driving system is suitable for completing the experiment of Confucian variable due to the constant load for a long time, but it needs to overcome a large friction force, and it is difficult to load a large load and deform; one is to drive through a motor and clutch matching (CN 1013809B), the method driven by this one motor is easy to realize synchronous and center-symmetrical loading, but due to the limitation of the geometric structure of the equipment, various biaxial loading paths cannot be realized, and the equipment in the invention patent CN1013809B can only Complete the tensile test; there is also a driving system with half a motor to achieve biaxial loading through four sets of double-acting transmission and feedback systems, (Experimental mechanics, 34, 1-9, 1994) There is a DC motor in each transmission system and an AC motor, which respectively realize the slow experimental state and the fast moving state, and can complete the quasi-static biaxial tension and compression experiments with arbitrary loading ratios, but it cannot realize the dynamic fatigue experiments under biaxial loads, and its There is no synchronous feedback in the fast moving state, and the clamping center of the specimen is determined by the LVDT value, which brings trouble to the installation of the specimen, and the bending of the horizontal loading device due to its own weight is avoided by suspending heavy objects

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