CN111737903B

CN111737903B - High-frequency performance prediction method of connector under vibration stress

Info

Publication number: CN111737903B
Application number: CN202010591952.0A
Authority: CN
Inventors: 李庆娅; 高锦春; 谢刚; 周雨奇; 王紫任; 毕凌宇; 宋凯旋; 王文佳; 罗俊宇
Original assignee: Beijing University of Posts and Telecommunications
Current assignee: Beijing University of Posts and Telecommunications
Priority date: 2020-06-24
Filing date: 2020-06-24
Publication date: 2022-12-20
Anticipated expiration: 2040-06-24
Also published as: CN111737903A

Abstract

The invention discloses a high-frequency performance prediction method of a connector under the action of vibration stress. The invention comprises the following steps: step one), constructing a vibration experiment platform, carrying out vibration degradation experiments of different degrees on the conductor in the jack of the N-type radio frequency coaxial connector, and measuring the contact pressure and high-frequency parameters of the connector under different degradation degrees; step two), establishing an equivalent circuit model comprising a transmission line and a degraded contact surface, wherein the contact surface model comprises contact resistance, capacitance and inductance parameters; step three), establishing a relation model of contact resistance, capacitance and contact pressure respectively according to the elastic Hertz contact theory and a roughness model of a contact surface, establishing a relation model of inductance and equivalent length, establishing a finite element simulation model of deformation quantity and equivalent length of the loose jack, and obtaining a relation model of contact pressure, deformation quantity and equivalent length; and step four), based on the actually measured contact pressure and the established relation model, the corresponding resistance, capacitance and inductance are substituted into the circuit model for simulation, so that the high-frequency performance under different contact pressures is predicted and compared with the test result. According to the method, the high-frequency performance prediction method of the connector under the action of the vibration stress is researched from the aspects of experimental design and theoretical derivation through the mechanism analysis of the connector jack looseness and the contact pressure reduction caused by vibration, and the method is suitable for analyzing all coaxial connectors with similar structures.

Description

High-frequency performance prediction method of connector under action of vibration stress

Technical Field

The invention relates to a high-frequency performance prediction method of a connector under the action of vibration stress, which is established on the basis of comprehensive analysis methods such as theoretical modeling and finite element simulation and the like under different degradation conditions and belongs to the technical field of electrical contact reliability of a communication system.

Background

The connector is used as a basic component, is mainly used for realizing the transmission and control of electric signals and the electric connection function between electronics and electrical equipment, is widely applied to various fields of aerospace, aviation, military equipment, electronics, communication and the like, and the safety and the reliability of the connector directly influence the safe and reliable operation of a system. The contact member composed of the contact pin and the jack is a core part of the connector, and the inserting and extracting processes are main modes for realizing electric connection, so that the contact member inside the connector is easily subjected to mechanical abrasion, the contact state is changed, the reliability of the connector is influenced, and the reliability of a system is further influenced to a certain degree.

Connectors are subject to a variety of environmental stresses during storage and use, with vibrational stresses being one of the major environmental factors affecting connector reliability. Under the action of the vibration stress, the relative motion between the plug hole and the plug pin of the connector is generated. Under the repeated action of long-term vibration stress, the jack can generate micro deformation, the phenomena of stress relaxation and elastic fatigue occur, the contact pressure is reduced, the contact performance of the connector is degraded, and the reliability is reduced. Degradation of the contact surfaces of the connector can degrade electrical parameters including contact resistance, high frequency parameters (insertion loss, return loss, voltage standing wave ratio, etc.), passive intermodulation, electromagnetic compatibility, etc., thereby affecting the proper transmission of communication signals.

Therefore, it is necessary to establish a method for predicting the high-frequency performance of the connector under the action of vibration stress, so as to provide a certain reference for reliability evaluation of the connector and establishment of a connector quality detection standard.

Disclosure of Invention

In view of the above technical problems, the present invention provides a method for predicting high frequency performance under the action of vibrational stress, which is suitable for the research of predicting high frequency performance of a device under the action of stress.

In order to meet the requirements, the invention provides the following scheme:

step one) accelerated test and degradation test

Firstly, a vibration experiment platform is built by adopting a signal source, an amplifier and a vibration table, a clamp required by the experiment is designed and processed, then an N-type contact pin and an N-type female-to-female connector are fixed on the vibration table by using the clamp, and then vibration acceleration tests are respectively carried out on the connector for 15 hours and 30 hours. The N-type male pin and the N-type female-to-female connector were removed, and the deformation of the insertion hole of the N-type female-to-female connector was observed to different degrees. The maximum stiction was obtained by testing an N-type connector pin and female-to-female connector using a tensile machine without vibration testing, resulting in contact pressures of 5.35n,3.27n and 0.62N for samples of connectors that were not degraded and subjected to vibration testing for 15 hours and 30 hours, respectively. The high-frequency parameters of the connector samples are measured by a vector network analyzer, and the analysis frequency is 0.1 MHz-1.0 GHz.

Step two) equivalent circuit and parameter modeling

When a vector network analyzer is used for testing a connector sample, the outer sides of the N-type female-to-female connectors are respectively connected with the SMA-type male-to-N-type female connectors for connection with the analyzer. Considering that certain contacts exist when the three connectors are connected and the connectors are equivalent to transmission lines, an equivalent circuit model comprising the transmission lines and degraded contact surfaces is established, and the model comprises contact resistance, capacitance and inductance parameters. By testing the surface roughness of the N-type contact pin in the original state, the contact surface is equivalent to a complete elastic Hertz contact, and a relation model of contact resistance, capacitance and contact pressure is respectively established. And (3) considering the influence of the contact pressure on the inductance, introducing an equivalent length parameter, and establishing a relation model of the parameter and the inductance. After the N-type female-to-female connector is subjected to a vibration experiment, the jack can be loosened, and the loosening degree is measured by introducing the deformation parameter of the loosening of the jack. And establishing a finite element simulation model of the deformation quantity and the equivalent length of the loose jack to obtain different relation models of the deformation quantity, the equivalent length and the contact pressure of the loose jack.

Step three) prediction of high-frequency performance parameters

And obtaining corresponding resistance, capacitance and inductance according to the actually measured contact pressure and the established relation model of the contact resistance, capacitance, inductance and contact pressure, and substituting the resistance, capacitance and inductance into the established circuit model for simulation, thereby predicting the high-frequency performance under different contact pressures and comparing the high-frequency performance with the test result.

The high-frequency performance prediction method of the connector under the action of the vibration stress predicts the high-frequency performance of the connector after the connector is inserted and exposed in a vibration environment for a certain time based on comprehensive analysis methods such as theoretical modeling, finite element simulation and the like, provides theoretical support for the high-frequency performance prediction of a device under the action of the stress, and is suitable for the high-frequency performance prediction of the related device under the action of the stress. The invention has the following advantages: predicting the high-frequency performance based on the jack stress relaxation phenomenon caused by the connector under the action of the vibration stress; aiming at an equivalent circuit model of the connector, a relation model of contact resistance, capacitance, inductance and contact pressure is established; the simulation simulates the high-frequency performance under the action of different contact pressures.

Drawings

FIG. 1 is a schematic diagram of the technical scheme of the invention.

Detailed Description

The invention is explained in detail below with reference to the figures and the implementation steps. The following description case uses an N-type female-to-female rf coaxial connector as a research object, but the present embodiment is not limited to the present invention, and the high frequency performance prediction can be performed by using the analysis method of the present invention whenever the coaxial structure of the present invention is used as an analysis object.

As shown in fig. 1, the method for predicting the high-frequency performance of the coaxial connector mainly includes surface physical modeling and experimental testing, and a method combining theoretical analysis and finite element simulation is used to establish the high-frequency performance prediction of the jack inner conductor of the coaxial connector under the action of vibration stress.

The method comprises the following steps of firstly, developing an acceleration test, and carrying out vibration degradation tests of different degrees on the jacks of the N-type connector. A vibration experiment platform is built by adopting a signal source, an amplifier and a vibration table, a clamp required by the experiment is designed and processed, then an N-type contact pin and an N-type female-to-female connector are fixed on the vibration table by using the clamp, and then vibration acceleration tests are respectively carried out on the connector for 15 hours and 30 hours. The N-type male pin and the N-type female-to-female connector were removed, and the deformation of the insertion hole of the N-type female-to-female connector was observed to different degrees. The maximum stiction was obtained by testing an N-type connector pin and female turn connector without vibration test using a tensile machine, thereby obtaining contact pressures of 5.35n,3.27n and 0.62N for connector samples that were not degraded and subjected to vibration tests for 15 hours and 30 hours, respectively. The high-frequency parameters of the connector samples are measured by a vector network analyzer, and the analysis frequency is 0.1 MHz-1.0 GHz.

And secondly, when a vector network analyzer is used for testing a connector sample, in order to be connected with the analyzer, the outer sides of the N-type female-to-female connectors are respectively connected with the SMA-type male-to-N-type female connectors. Considering that there is a certain contact when these three connectors are connected and the connectors are equivalent to a transmission line, an equivalent circuit model including the transmission line and the degraded contact surface is established, which contains contact resistance, capacitance and inductance parameters. By testing the surface roughness of the N-type contact pin in the original state, the contact surface is equivalent to a complete elastic contact, and the relation models of contact resistance, capacitance and contact pressure are respectively established. And (3) considering the influence of the contact pressure on the inductance, introducing an equivalent length parameter, and establishing a relation model of the parameter and the inductance. After the N-type female-to-female connector is subjected to a vibration experiment, the jack can be loosened, and the loosening degree is measured by introducing the deformation parameter of the loosening of the jack. And establishing a finite element simulation model of the deformation quantity and the equivalent length of the loose jack to obtain different relation models of the deformation quantity, the equivalent length and the contact pressure of the loose jack.

And thirdly, obtaining corresponding resistance, capacitance and inductance values according to the actually measured contact pressure and the established relation model of the contact resistance, capacitance, inductance and contact pressure, and then substituting the corresponding resistance, capacitance and inductance values into the established circuit model for simulation, thereby predicting the high-frequency performance under different contact pressures and comparing the high-frequency performance with the test result.

Claims

1. A high-frequency performance prediction method of a connector under the action of vibration stress is characterized by comprising the following steps:

the method comprises the following steps: the method comprises the steps of building a vibration experiment platform, degrading the connector to different degrees through a vibration acceleration test, determining connector samples with different degradation degrees, and testing contact pressure and high-frequency performance parameters of the connector samples;

step two: establishing an equivalent circuit model comprising a transmission line and a degraded contact surface, wherein the equivalent circuit model comprises contact resistance, capacitance and inductance parameters; establishing a first relation model of contact resistance, capacitance and contact pressure respectively according to an elastic Hertz contact theory and a roughness model of a contact surface, establishing a relation model of inductance and equivalent length, establishing a finite element simulation model of deformation quantity and equivalent length of loose jacks, and obtaining a second relation model of contact pressure, deformation quantity and equivalent length;

step three: and obtaining corresponding resistance, capacitance and inductance according to the actually measured contact pressure and the established first relation model and the second relation model, and substituting the resistance, capacitance and inductance into the equivalent circuit model for simulation, thereby predicting the high-frequency performance under different contact pressures and comparing the high-frequency performance with the test result.