Cold Extrusion Enhanced Friction Coefficient Test Method for Metal Hole Structures
A friction coefficient and test method technology, applied in the field of testing, can solve the problems such as the inability to realize the measurement of the friction coefficient in the cold extrusion strengthening process, the complicated device and the measurement process, and the inability to measure the frictional resistance, and achieve a simple and reliable measurement method and a calculation model. Simple and practical, low cost effect
Active Publication Date: 2020-11-06
SICHUAN UNIV
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However, the device and measurement process involved in this method are more complicated, and different installation mold bases need to be designed and processed for different test objects, and the time and economic costs are relatively high
In addition, for the strengthening process of cold extrusion, the tensile force measured in the axial direction of the mandrel is the strengthening resistance, which is composed of friction resistance and shear resistance. This method can only measure the strengthening resistance, not the accurate friction resistance, so it cannot Realize the measurement of friction coefficient in cold extrusion strengthening process
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[0031] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.
[0032] Such as figure 1 As shown, the embodiment of the present invention provides a method for testing the coefficient of friction of a metal pore structure through cold extrusion strengthening, including the following steps S1 to S4:
[0033] S1. According to the cold extrusion strengthening process of the isotropic metal material pore structure, the relationship model between the radial compressive stress of the extrusion hole and the strengthening amount is established by using the Latin American formula;
[0034] In this embodiment, the present invention uses the Lamè formula to establish a r...
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The invention discloses a cold extrusion strengthening friction coefficient testing method of a metal hole structure. The method comprises the following steps: establishing a mathematical model of theradial pressure stress of the metal hole structure about the strengthening amount by utilizing a Lame formula; combining the structure and strengthening characteristics of the metal hole structure inthe cold extrusion strengthening process; establishing a reinforced resistance theoretical model based on a coulomb friction principle, finally measuring a reinforced resistance-displacement curve through a reinforced resistance measuring device, analyzing curve characteristics, carrying out linear fitting on a curve linear frictional resistance stage, and substituting fitting parameters into thetheoretical frictional resistance model to calculate the friction coefficient of a core rod and an extrusion hole wall. Effective testing of the friction coefficient of the core rod and the extrusionhole wall in the cold extrusion process of the metal hole structure is achieved, key parameters are provided for research and engineering application of the cold extrusion strengthening technology, and the method has the advantages of being high in calculation efficiency, high in accuracy, low in cost, high in engineering applicability and the like.
Description
technical field [0001] The invention belongs to the testing field, and in particular relates to a friction coefficient test method between a mandrel rod and a connection hole wall during the cold extrusion strengthening process of a metal hole structure. Background technique [0002] Cold extrusion strengthening is currently the main means to increase the fatigue life of the metal hole structure, which can significantly improve the fatigue life of the hole structure, and has the advantages of not changing the material and structure design, no weight gain, low cost, obvious strengthening effect, and a wide range of application hole diameters. , has been widely used in fatigue strengthening of connection holes of key load-bearing components in aircraft fuselage and wings. [0003] During the strengthening process of cold extrusion, the extrusion mandrel and the connecting hole have an interference fit, and the mandrel and the connecting hole produce obvious strengthening resis...
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IPC IPC(8): G01N19/02B21C51/00
CPCB21C51/00G01N19/02
Inventor 左杨杰曹增强曹跃杰杨宝惠张岐良钟山
Owner SICHUAN UNIV