A method and system for predicting the interface resistance of a pair of contactors based on single spot electrical contact characteristics

Abstract

A kind of pairing contact interface resistance prediction method and system based on single spot electric contact characteristic, belong to electric contact reliability and electric connector performance prediction technical field.For solving the problem that contact resistance prediction method is difficult to reflect local contact load difference simultaneously, the present application measures single spot contact resistance under different pressure load and load current combination by probe, establishes single spot electric contact characteristic model with normalized pressure load, load current as input, single spot contact resistance as output;According to surface topography and assembly relationship, determine the discrete contact area under the set indentation amount and its local pressure load, equivalent curvature radius and normalized pressure load;Each area is mapped as parallel conductive branch, the nonlinear relationship of branch contact resistance with current is determined by model, and the interface resistance prediction value is outputted under the constraint of common interface voltage drop and total current conservation by iterative solution with the ratio of voltage drop and total current.The present application is used for conductive performance evaluation and structure optimization.

Description

Technical Field

[0001] This invention relates to the field of electrical contact reliability and electrical connector performance prediction technology, and particularly to the modeling and prediction of interface resistance of mating contacts under different contact loads and current flow conditions. Specifically, it relates to a method and system for predicting interface resistance of mating contacts based on single-spot electrical contact characteristics. Background Technology

[0002] Mating contacts transmit electrical energy or signals through their contacting conductive surfaces and are widely used in electrical connectors and electrical connection structures. Their interface resistance directly affects conductivity loss, contact temperature rise, and connection reliability, making it a crucial parameter for contact design and performance evaluation. Due to the microscopic roughness of the contact surfaces, actual conductivity occurs in multiple discrete contact regions, each with different geometric dimensions, load conditions, and conductivity. Therefore, establishing a quantitative relationship between local contact states, current flow conditions, and overall interface resistance is of great significance for predicting the performance and optimizing the structure of mating contacts.

[0003] Existing methods for calculating contact resistance typically determine the contact area based on surface morphology and contact mechanics models, then use classical electrical contact formulas to calculate the resistance of each contact spot, and finally obtain the interface resistance through parallel calculations. For example, patent CN114530218B reconstructs micro-protrusions based on measured rough surfaces, combining elastoplastic contact analysis and contact spot resistance calculations to predict the contact resistance of rough surfaces. However, its spot resistance is mainly determined by the contact size and material resistivity, without considering local current as an independent input, making it difficult to directly describe the current redistribution between spots and the changes in contact resistance caused by changes in current flow conditions.

[0004] The resistance at actual contact points is influenced by a combination of mechanical, electrical, and thermal effects. Contact loads cause deformation of the surface and substrate, altering the actual contact area and potentially leading to rupture of the surface film and the formation of conductive channels. Current flowing through the minute contact area generates localized Joule heating, causing changes in temperature and material resistivity. Under appropriate current-carrying conditions, this can also lead to material softening or localized melting, further altering the contact state. Therefore, even with the same external contact load, contact resistance can vary significantly under different current-carrying conditions. Calculating spot resistance solely based on contact area and fixed material resistivity is insufficient to comprehensively reflect these coupling effects.

[0005] In an interface with multiple points of conduction, the local current carried by each point is usually not equal. The local current is determined by the resistance of each branch and the overall conductive network, while the branch resistance changes with its own current; the two are interrelated. Applying a given total current directly to each point, or distributing the current evenly according to the number of points, fails to accurately reflect the actual current flow state. Pre-determining fixed point resistances before performing parallel calculations also fails to describe the feedback of local resistance changes on current distribution. Therefore, considering the local current in each contact region and its interaction with the contact resistance is crucial for predicting interface resistance under different current flow conditions.

[0006] Single-spot testing can directly obtain contact resistance under different load and current conditions. The measurement results comprehensively reflect the conductivity characteristics under the combined effects of contact deformation, surface film state, and current-thermal effects, providing experimental basis for resistance modeling of actual contact interfaces. However, the load conditions of single-spot testing are usually represented by the actual pressure load between the probe and the contact element. The load-bearing state of each discrete contact region in the actual interface depends on the geometric and material parameters of that region. The lack of a unified benchmark makes it difficult to directly transfer single-spot test data to multi-spot contact interfaces. Furthermore, when using single-spot characteristics for multi-spot interface prediction, it is necessary to coordinate the solution of local currents and contact resistances in each contact region. Therefore, it is necessary to establish a prediction method that correlates the measured electrical contact characteristics of single-spot testing, local contact states, and multi-branch current distribution, providing a basis for evaluating and optimizing the conductivity performance of paired contacts under different load and current conditions. Summary of the Invention

[0007] The problem to be solved by the present invention is that existing contact resistance prediction methods are unable to simultaneously reflect the differences in local contact load, the change of single-spot contact resistance with current, and the current distribution between contact areas. The present invention proposes a method and system for predicting the interface resistance of paired contact components based on the characteristics of single-spot electrical contact.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics includes the following steps:

[0010] S1. A single contact spot is formed by applying a probe to the contact element. The contact resistance of the single spot is measured under different combinations of pressure load and load current, and a single-spot electrical contact characteristic dataset is constructed.

[0011] S2. Based on the single-spot electrical contact characteristic dataset obtained in step S1, a single-spot electrical contact characteristic model is established with normalized pressure load and load current as inputs and single-spot contact resistance as output. The normalized pressure load is the ratio of the pressure load to the critical pressure load corresponding to the initial yield at the contact point.

[0012] S3. Obtain multiple discrete contact areas formed by the contact interface of the mating contact members under a set indentation amount, as well as the local pressure load and local equivalent radius of curvature of each discrete contact area, and calculate the normalized pressure load of each discrete contact area based on the ratio of the local pressure load of each discrete contact area to the critical pressure load corresponding to the initial yield of the discrete contact area.

[0013] S4. Construct each discrete contact region obtained in step S3 into a parallel conductive branch connected between the paired contact members. Input the normalized pressure load of each discrete contact region and the corresponding branch current to be determined into the single-spot electrical contact characteristic model established in step S2 to determine the nonlinear relationship between the contact resistance of each branch and the branch current.

[0014] S5. Based on the relationship between the contact resistance and the current of each branch obtained in step S4, and with each branch having the same interface voltage drop and the given total current corresponding to the sum of the currents of each branch as constraints, and with the common interface voltage drop as the iterative variable, solve the current of each branch and the interface voltage drop simultaneously and iteratively; when the absolute value of the total current conservation residual of the difference between the sum of the currents of each branch and the given total current is less than the preset tolerance, output the current of each branch and the common interface voltage drop; otherwise, use a root search algorithm with upper and lower bounds to update the trial value of the interface voltage drop and then solve the current of each branch again.

[0015] S6. Divide the common interface voltage drop obtained in step S5 by the given total current to output the predicted interface resistance value of the mating contacts under the conditions of set pressure and given total current.

[0016] Furthermore, in step S1, the probe and the contact have the same surface material, and the radius of curvature of the probe tip is on the order of micrometers or nanometers, so that there is only a single contact spot between the probe and the contact during the measurement process.

[0017] The probe is moved along the contact normal direction between the probe and the contact element to apply and continuously adjust the pressure load; a load current is applied between the probe and the contact element, and the contact voltage drop is measured based on the four-wire method, with the voltage test line placed close to the contact point to eliminate the influence of the probe and contact element's body resistance; the pressure load F is simultaneously acquired. c Load current I and contact voltage drop U c , and press R c = U c / I Calculate the contact resistance R of a single spotc ;

[0018] The single-spot electrical contact characteristic dataset is a collection of curves showing the variation of single-spot contact resistance with pressure load under different load currents.

[0019] Furthermore, the single-spot electrical contact characteristic dataset is a collection of curves showing the change of single-spot contact resistance with pressure load under different load currents; the measured single-spot contact resistance is a comprehensive reflection of the mechanical, electrical, and thermal coupling effects, such as the elastic-plastic deformation of the surface film and substrate caused by pressure load, film fragmentation, and softening or melting caused by the thermal effect of load current at the contact point.

[0020] Furthermore, in step S2, based on the equivalent radius of curvature R, equivalent elastic modulus E, and equivalent hardness H at the single-spot contact point, the critical pressure load F corresponding to the initial yield at the contact point is calculated using the following formula. cri :

[0021] F cri = (πKH) 3 R 2 / (6E 2 )

[0022] Where K is the hardness coefficient, K = 0.454 + 0.41ν, and ν is the Poisson's ratio of the surface material; normalized pressure load. F c This is a pressure load.

[0023] Furthermore, in step S2, the normalized pressure load is... With load current I as the input variable and single-spot contact resistance R as the input variable... c To construct a single-spot electrical contact characteristic model for the output variables:

[0024]

[0025] Wherein, P3(·,·) is a third-order bivariate polynomial in terms of normalized pressure load and load current, and the parameter to be identified is a. mn Let m be the coefficients of the terms of the third-order bivariate polynomial, and m be the normalized pressure load in each term of the third-order bivariate polynomial, where m ranges from 0 to 3 and n = 3 - m. The power exponent of , where n is the power exponent of the load current I in each term of the third-order bivariate polynomial;

[0026] The normalized pressure load and load current of each group in the single-spot electrical contact characteristic dataset are substituted into a third-order bivariate polynomial about the normalized pressure load and load current. With the goal of minimizing the fitting error between the calculated predicted contact resistance value and the corresponding measured value, each parameter to be identified is identified and determined to obtain the single-spot electrical contact characteristic model. The effective current range of the single-spot electrical contact characteristic model is determined by the range of the load current in the single-spot electrical contact characteristic dataset.

[0027] Furthermore, in step S3, the surface height data of the two contact surfaces of the paired contact parts are obtained and virtual assembly is performed according to the assembly relationship. The local positive geometric interference between the two contact surfaces is calculated according to the set pressing amount, and the interconnected interference nodes are merged into a discrete contact area.

[0028] For each discrete contact region, local surface fitting is performed on the two contact surfaces, and the equivalent radius of curvature of the discrete contact region is calculated. Based on the surface material parameters and the local equivalent radius of curvature of each discrete contact region, the critical pressure load corresponding to the initial yield of the discrete contact region is calculated, and the local pressure load is calculated in combination with the local indentation of the discrete contact region, thereby obtaining the normalized pressure load of each discrete contact region.

[0029] Furthermore, in step S5, the common interface voltage drop is used as the iteration variable, and its trial value V is set. c ;

[0030] Furthermore, in step S5, the product of the contact resistance of each branch and the current of that branch is set to equal the trial value V of the interface voltage drop. c Within the effective current range of the single-spot electrical contact characteristic model, solve for the branch current I respectively. i Subtract the given total current I from the sum of the currents in each branch. tot The total current conservation residual Ψ(V) is obtained. c );

[0031] When |Ψ(V c When the current is less than the preset tolerance ε, the current I of each branch is output. i and common interface voltage drop V c Otherwise, a root search algorithm with upper and lower bounds is used in the bounded search interval [V]. min V max After updating the trial value of the interface voltage drop, the solution is recalculated, V min V is the lower bound of the root search interval for the common interface voltage drop. max This is the upper bound of the root search interval for the common interface voltage drop;

[0032] Furthermore, root search algorithms include binary search or bounded Brent search;

[0033] The common interface voltage drop V c Divide by the given total current I tot The predicted value R of the interface resistance of the mating contacts is obtained. cp = V c ' / I tot ; reduce the common interface voltage drop V c Divide by the current in each branch I i The contact resistance R of each branch is obtained. c,i = V c ' / I i .

[0034] Furthermore, mating contacts are disposed within the electrical connector; in step S6, the predicted interface resistance value R is obtained. cp Then, the volume resistance R of each conductive component is determined based on the conductive path of the electrical connector. b = ρl / A, where ρ, A, and l are the resistivity, cross-sectional area, and length of the conductive component, respectively; the predicted interface resistance is combined with the volume resistance of each conductive component in series and parallel topology according to the actual current path in the electrical connector to calculate the predicted total resistance R between the external terminals of the electrical connector. s .

[0035] A system for predicting the interface resistance of mating contacts based on single-spot electrical contact characteristics includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the computer program is executed, it implements the steps of the method for predicting the interface resistance of mating contacts based on single-spot electrical contact characteristics.

[0036] Furthermore, the system includes a single-spot testing module, which is used to form a single contact spot with the contact element through a probe, and to obtain single-spot contact resistance measurement data under different combinations of pressure loads and different load currents.

[0037] The single-spot electrical contact characteristic model construction module is used to acquire single-spot contact resistance measurement data, probe geometric parameters, and contact material parameters; calculate the initial yield critical pressure load at the test contact; normalize the measured pressure load; and establish a single-spot electrical contact characteristic model through parameter identification, using the normalized pressure load and load current as inputs and the single-spot contact resistance as outputs. This module saves the model coefficients, variable units, and effective current range, and provides a model calling interface to the branch current allocation module.

[0038] The contact state acquisition module is used to receive surface topography height data, assembly conditions and material parameters of the two contact parts of the paired contact parts, obtain discrete contact areas and their local mechanical parameters through surface interferometry, and output spatial position associated with area number, local pressure load, local equivalent radius of curvature and normalized pressure load.

[0039] The branch current distribution module maps each discrete contact area to a parallel conductive branch. Based on the normalized pressure load of each discrete contact area, it calls the single-spot electrical contact characteristic model to establish the nonlinear relationship between the contact resistance of each branch and the current of that branch. With the constraint that each branch has the same interface voltage drop and the sum of the currents of each branch equals the given total current, it iteratively solves the current of each branch using the common interface voltage drop as the iterative variable. When the absolute value of the total current conservation residual is less than the preset tolerance, it outputs the common interface voltage drop, the current of each branch, and the contact resistance of each branch.

[0040] The interface resistance determination module is used to divide the common interface voltage drop by a given total current and output the predicted interface resistance value of the mating contacts.

[0041] The beneficial effects of this invention are:

[0042] The present invention discloses a method for predicting the interface resistance of mating contacts based on single-spot electrical contact characteristics. This method can quantitatively predict the interface resistance of mating contacts under different pressure loads and load currents, establish the relationship between local contact state and overall conductivity, and provide a calculation basis for evaluating the conductivity performance of electrical connectors, selecting assembly parameters, and optimizing structural design.

[0043] The present invention provides a method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics. This method can introduce the electrical contact characteristics of the actual contact surface under the combined action of pressure load and load current into the prediction model through single-spot testing and parameter identification. This allows the calculation of local contact resistance to be supported by measured data, reflecting the influence of surface state and load current on conductivity, in addition to contact geometry and material resistivity.

[0044] The present invention discloses a method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics. By normalizing the pressure load with the critical pressure load corresponding to the initial yield at the contact, a unified corresponding benchmark is established between the single-spot test conditions and the local load-bearing state of the actual interface. This allows the measured electrical contact characteristics of the single spot to be extrapolated to multi-spot contact interfaces, while retaining the influence of surface morphology and load distribution differences on the interface resistance.

[0045] The present invention provides a method for predicting the interface resistance of paired contacts based on the characteristics of single-spot electrical contacts. This method can associate local contact loads, branch resistances, and current distribution within the same computational framework. By simultaneously solving the common interface voltage drop and total current conservation constraints through iterative solutions, it reflects the changes in contact resistance caused by changes in branch current and their impact on current redistribution, thereby enabling the prediction of the interface resistance of current-dependent multi-spot conductive networks.

[0046] The present invention provides a method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics. This method can obtain the contact resistance and branch current distribution of each discrete contact area while outputting the overall interface resistance, identify current concentration areas and local conductivity differences, and provide a basis for analyzing the weak points of the contact interface, adjusting the contact structure and improving the load distribution.

[0047] The present invention discloses a method for predicting the interface resistance of mating contacts based on single-spot electrical contact characteristics. This method can perform single-spot tests on corresponding materials and surface conditions, and can be applied to mating contacts with different contact materials, plating, and structural forms. It can also be used to compare the effects of surface morphology, assembly state, contact load, and load current on conductivity. Furthermore, it can be combined with the bulk resistance of conductive components to predict the total resistance of electrical connector terminals, providing methodological support for the design analysis and engineering application evaluation of different types of electrical connectors. Attached Figure Description

[0048] Figure 1 This is a flowchart illustrating a method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics according to the present invention.

[0049] Figure 2 This is a schematic diagram of a single-spot contact resistance testing device;

[0050] Figure 3 The measured curves of single-spot contact resistance versus pressure load under different load currents are shown.

[0051] Figure 4 The fitted surface plot of the single-spot contact resistance as a function of normalized pressure load and load current;

[0052] Figure 5 This is a virtual assembly diagram of the two contact surfaces of the mating contact components;

[0053] Figure 6 A schematic diagram of the discrete contact areas formed by mating contacts under a set overall indentation amount;

[0054] Figure 7 The flowchart shows the iterative solution process for branch current and common interface voltage drop.

[0055] Figure 8 A schematic diagram of the equivalent resistance network of an electrical connector, including interface resistance and the volume resistance of conductive components.

[0056] Figure 9 This is a comparison chart of the predicted and measured total resistance of the external terminals of the electrical connector when the total current is 1 mA.

[0057] Figure 10This is a comparison chart of the predicted and measured total resistance of the external terminals of the electrical connector when the total current is 100 mA. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described specific embodiments are merely a part of the embodiments of the invention, and not all of them. The components of the specific embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations, and the invention may also have other embodiments.

[0059] Therefore, the following detailed description of specific embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected specific embodiments of the invention. All other specific embodiments obtained by those skilled in the art based on these specific embodiments without inventive effort are within the scope of protection of this invention.

[0060] To further understand the invention's content, features, and effects, the following specific embodiments are provided, along with accompanying drawings. Figure 1 -Appendix Figure 10 Detailed explanation is as follows:

[0061] Example 1:

[0062] This embodiment provides a method for predicting the interface resistance of paired contacts based on the characteristics of single-spot electrical contacts, such as... Figure 1 As shown, it includes the following steps:

[0063] S1. A single contact spot is formed by applying a probe to the contact element. The contact resistance of the single spot is measured under different combinations of pressure loads and load currents, and a dataset of single-spot electrical contact characteristics is constructed.

[0064] In this step, the probe and the contact have the same surface material, and the radius of curvature of the probe tip is on the order of micrometers or nanometers, to ensure that there is only a single contact spot between the probe and the contact during the measurement process.

[0065] like Figure 2 As shown, the loading device 1 moves the probe along the contact normal direction between the probe 2 and the contact 3 to achieve the application and continuous adjustment of the pressure load; the constant current source 5 applies a load current I between the probe 2 and the contact 3, and the voltage measurement unit 6 measures the contact voltage drop U between the probe and the contact based on the four-wire method. cFurthermore, the voltage test leads are positioned close to the contact point (i.e., contact spot 4) to eliminate the influence of the probe and contact body resistance on the measurement results; the data acquisition unit 7 synchronously acquires the pressure load F. c Load current I and contact voltage drop U c The contact resistance R of a single spot is calculated according to the following formula. c :

[0066] R c = U c / I

[0067] The single-spot electrical contact characteristic dataset is a collection of curves showing the change of single-spot contact resistance with pressure load under different load currents. The measured single-spot contact resistance is a comprehensive reflection of the mechanical, electrical, and thermal coupling effects, such as the elastic-plastic deformation of the surface film and substrate caused by pressure load, film fragmentation, and softening or melting caused by the thermal effect of load current at the contact point.

[0068] S2. Based on the single-spot electrical contact characteristic dataset obtained in step S1, establish a single-spot electrical contact characteristic model with normalized pressure load and load current as inputs and single-spot contact resistance as output.

[0069] In this step, the critical pressure load F corresponding to the initial yield at the contact point is first calculated using the following formula. cri :

[0070] F cri = (πKH) 3 R 2 / (6E 2 )

[0071] Where R is the equivalent radius of curvature at the single-spot contact point, determined by the radius of curvature of the probe tip and the radius of curvature of the contact element at that contact point; E is the equivalent elastic modulus, determined by the elastic modulus and Poisson's ratio of the probe and contact element materials; H is the equivalent hardness, taken as the hardness of the softer material in the probe and contact element under the corresponding surface state; K is the hardness coefficient, K = 0.454 + 0.41ν, where ν is the Poisson's ratio of the surface material. The normalized pressure load is thus obtained. .

[0072] Then, normalized pressure load With load current I as the input variable and single-spot contact resistance R as the input variable... c To construct a single-spot electrical contact characteristic model for the output variables:

[0073]

[0074] Wherein, P3(·,·) is a third-order bivariate polynomial in terms of normalized pressure load and load current, and the parameter to be identified is a. mn(m = 0, 1, 2, 3; n = 0, 1, …, 3-m) are the coefficients of the three-order bivariate polynomial, and there are 10 coefficients.

[0075] Because the single-spot electrical contact characteristic model has certain limitations regarding the parameter to be identified, a mn It is linear. Substituting the normalized pressure load, load current, and corresponding measured single-spot contact resistance of each group in the single-spot electrical contact characteristic dataset into a third-order bivariate polynomial, it can be written as a linear system of equations in the form of R = Φa, where R is a column vector composed of measured single-spot contact resistances, Φ is a design matrix constructed from each group of normalized pressure loads and load currents according to the third-order bivariate polynomial, and a is the parameter to be identified. mn The column vector is formed; with the goal of minimizing the fitting error between the calculated predicted contact resistance value and the corresponding measured value, according to a = (Φ T Φ) -1 Φ T R can be used for least squares identification, or an iterative identification method aimed at minimizing the sum of squares of the relative fitting errors can be employed to determine the coefficients a. mn A single-spot electrical contact characteristic model is obtained to characterize the variation law of single-spot contact resistance under the combined action of pressure load and load current, such as... Figure 4 As shown.

[0076] The effective current range of the single-spot electrical contact characteristic model is determined by the range of the load current in the single-spot electrical contact characteristic data set. In this embodiment, the effective current range is from 0.1 mA to 100 mA. In subsequent steps, the solution of the current of each branch is performed within this effective current range.

[0077] S3. Obtain multiple discrete contact areas formed by the contact interface of the mating contact members under a set indentation amount, as well as the local pressure load and local equivalent radius of curvature of each discrete contact area, and then calculate the normalized pressure load of each discrete contact area.

[0078] The specific implementation method for this step is as follows:

[0079] S3.1. Acquire the surface height data z of the two contact surfaces of the mating contact at a set sampling interval (e.g., 0.1 μm to 0.5 μm). A (x,y) and z B (x,y), and unify them into the same assembly coordinate system according to the assembly relationship of the paired contact parts;

[0080] S3.2. Perform virtual assembly of the two contact surfaces according to the assembly relationship, and set the total indentation along the contact normal direction as δ; for node (x,y), let the normal distance between the two contact surfaces before indentation be g(x,y), then the local positive geometric interference of this node is...

[0081] h(x,y) = max{0, δ - g(x,y)};

[0082] S3.3. Nodes with h(x,y) greater than 0 are identified as interference nodes; using the eight-neighbor connectivity criterion, interconnected interference nodes are merged into a discrete contact region; interference nodes with a number less than the preset minimum number of nodes N are removed. min (e.g. N) min Take the region from 1 to 2) to obtain N. c Discrete contact areas, such as Figure 5 and Figure 6 As shown;

[0083] S3.4. Perform quadratic surface fitting on the two contact surface nodes within the j-th discrete contact region respectively:

[0084] z = a1x 2 + a2y 2 + a3xy + a4x + a5y + a6;

[0085] The principal curvatures κ1 and κ2 of the surface in this region and their corresponding principal radii of curvature are calculated from the quadratic coefficients a1, a2, and a3 obtained from the fitting, thus obtaining the principal radii of curvature R of the two contact surfaces in this region. A,j and R B,j The equivalent radius of curvature R of the discrete contact region j satisfy

[0086] 1 / R j = 1 / R A,j + 1 / R B,j ;

[0087] S3.5. Based on the surface material parameters (equivalent elastic modulus) of the j-th discrete contact region. Equivalent hardness H j ) and equivalent radius of curvature R j The critical pressure load F corresponding to the initial yield of the discrete contact region is calculated using the same method as in step S2. cri,j The average value of the local positive geometric interference at each interference node within the discrete contact region is taken as the local indentation δ of that region. j The local pressure load in this area is calculated based on the relationship between the load and the indentation amount in elastic contact.

[0088] ;

[0089] When the calculated local pressure load F j Exceeding the critical pressure load F in this region cri,jAt that time, the local pressure load is corrected according to the elastoplastic contact model (e.g., the CEB model) to account for the effect of the contact area slowing down with the increase of indentation after material yielding; finally, the normalized pressure load of the j-th discrete contact region is calculated according to the following formula.

[0090] ;

[0091] It should be noted that the above methods for determining the equivalent radius of curvature and local pressure load are only examples. In actual implementation, the Hertz contact model, CEB elastoplastic contact model, or finite element simulation method can be used to directly obtain the local pressure load and equivalent radius of curvature of each discrete contact area.

[0092] S4. Construct each discrete contact region obtained in step S3 into a parallel conductive branch connected between the paired contact members. Input the normalized pressure load of each discrete contact region and the corresponding branch current to be determined into the single-spot electrical contact characteristic model established in step S2 to determine the nonlinear relationship between the contact resistance of each branch and the branch current.

[0093] In this step, the j-th discrete contact region is mapped to the j-th conductive branch. Each branch is connected in parallel between the two contacts of the mating contact, meaning each branch bears the same interface voltage drop. The normalized pressure load of the j-th discrete contact region is then... and the current I to be determined in this branch j Substituting the single-spot electrical contact characteristic model established in step S2, the relationship between the contact resistance and the current of this branch is obtained:

[0094] ;

[0095] This relationship shows that the contact resistance of each branch varies with its own current, and the volt-ampere characteristic of each branch is non-linear, meaning that the branch current and the interface voltage drop satisfy a certain relationship. .

[0096] S5. Based on the relationship between the contact resistance and the current of each branch obtained in step S4, with each branch having the same interface voltage drop and the sum of the currents of each branch equal to the given total current as constraints, and with the common interface voltage drop as the iterative variable, solve the current of each branch and the interface voltage drop simultaneously and iteratively until the absolute value of the total current conservation residual is less than the preset tolerance.

[0097] The specific implementation method of this step is as follows: Figure 7 As shown, it includes:

[0098] S5.1. Determine the lower bound V of the search interval for the interface voltage drop. min and the upper realm V max : By each branch in the effective current range [I min , Imax The current-voltage characteristic within the range can be obtained as follows:

[0099]

[0100] ;

[0101] S5.2. Set the trial value V of the interface voltage drop within the search interval. c For example, take V c = (V min + V max ) / 2;

[0102] S5.3. For the j-th branch, solve for the branch current I that satisfies the following equation within the effective current interval. j :

[0103] ;

[0104] Since the branch voltage drop increases monotonically with the branch current within the effective current range, the above equation applies to the interval [I... min , I max There is a unique solution within the memory, which can be obtained using the bisection method or the bounded Brent method to obtain the current I in each branch. j (j = 1, 2, …, N) c );

[0105] S5.4. Calculate the total current conservation residual:

[0106] Ψ(V c ) = Σ j=1 Nc I j - I tot ;

[0107] S5.5. When |Ψ(V c When the current is less than the preset tolerance ε, the total current is determined to be conserved, and the current I of each branch is output. j and common interface voltage drop V c Otherwise, since the current in each branch increases monotonically with the interface voltage drop, Ψ(V c Regarding V c Monotonically increasing, therefore when Ψ(V) c When V is greater than 0, let V min = V c When Ψ(V c When V is less than 0 max = V c Thus, within the bounded search interval [V] min V maxUpdate the trial value of the interface voltage drop and return to step S5.3 to continue solving; when the number of iterations reaches the preset upper limit (e.g., 100 times), terminate the iteration and output the current calculation result.

[0108] S6. Divide the interface voltage drop calculated in step S5 by the given total current to output the predicted interface resistance value of the mating contact under the conditions of set pressure and given total current.

[0109] In this step, the common interface voltage drop V c Divide by the given total current I tot The predicted value R of the interface resistance of the mating contacts is obtained. cp :

[0110] R cp = V c ' / I tot

[0111] At the same time, the common interface voltage drop V c Divide by the current I of each branch respectively j The contact resistance R of each discrete contact region is obtained. c,j = V c ' / I j .

[0112] Furthermore, mating contacts are disposed within the electrical connector. The predicted interface resistance value R is obtained in step S6. cp Then, the volume resistance of each conductive component is determined based on the conductive path of the electrical connector:

[0113] R b = ρl / A

[0114] Where ρ, A, and l represent the resistivity, cross-sectional area, and length of the conductive component, respectively. The predicted interface resistance is combined with the volume resistance of each conductive component in a series-parallel topology according to the actual current path in the electrical connector, resulting in the following... Figure 8 The equivalent resistance network is shown, and the predicted total resistance R between the external terminals of the electrical connector is calculated. s .

[0115] Example 2:

[0116] This embodiment is based on Embodiment 1 and is explained in the following description:

[0117] 1. Calculation Object

[0118] A case study was conducted using mating contacts of an electrical connector. The contacts utilize a beryllium copper substrate with an approximately 3 μm nickel interlayer and an approximately 3.2 μm hard gold surface layer. The mating contact surfaces are an arc surface and a flat surface, respectively. Through single-spot electrical contact characteristic testing, contact state calculation, and branch current determination, the interface resistance of the mating contacts was predicted. The total resistance of the external terminals of the electrical connector was calculated by combining this with the bulk resistance of the conductive components, and the results were compared with measured values.

[0119] 2. Calculation process

[0120] (1) According to step S1, adopt Figure 2 The apparatus shown, along with a gold-plated probe with a tip radius of 2.5 μm, was used to measure the single-spot contact resistance under currents ranging from 0.1 mA to 100 mA and a maximum pressure load of 0.6 N, yielding... Figure 3 The set of electrical contact characteristic curves shown.

[0121] (2) According to step S2, press The measured pressure load is normalized, where F cri Press F cri = (πKH) 3 R 2 / (6E 2 ) Calculate, and use least squares to identify the coefficients of the third-order bivariate polynomial, to obtain Figure 4 The single-spot electrical contact characteristic model is shown.

[0122] (3) According to step S3, the height data of approximately 450 μm × 450 μm regions on each of the two contact surfaces are obtained at a sampling interval of 0.125 μm. The local positive geometric interference is calculated according to h(x,y) = max{0, δ - g(x,y)}, and virtual assembly and discrete contact region identification are performed, such as... Figure 5 and Figure 6 As shown.

[0123] (4) According to step S4, each discrete contact region is constructed as a parallel conductive branch, and the corresponding normalized pressure load is substituted to establish the resistance-current relationship of each branch; according to step S5, according to Figure 7 The process shown uses the common interface voltage drop as the iteration variable and the total current conservation residual being less than the preset tolerance as the convergence criterion to iteratively solve for the branch current and the common interface voltage drop.

[0124] (5) According to step S6, calculate the interface resistance of the mating contacts, and combine it with the body resistance of the conductive components, according to... Figure 8 The equivalent resistance network shown is used to calculate the total resistance of the external terminals.

[0125] (6) Ten different surface locations were selected, and the predicted and measured values ​​of the total resistance were compared under loads ranging from 0.03 N to 0.60 N. The comparison results for total currents of 1 mA and 100 mA are as follows: Figure 9 and Figure 10 As shown.

[0126] 3. Calculate the revenue

[0127] (1) The total resistance of the external terminals of the electrical connector was calculated according to the method of the present invention. When the contact load was 0.03 N to 0.60 N and the total current was 1 mA and 100 mA, respectively, the relative root mean square error between the predicted value and the measured value was 6.14% and 9.32%, respectively, indicating that the method can predict the resistance change under different load and current conditions.

[0128] (2) Based on the measured data of a single spot, the coefficients of the third-order bivariate polynomial were identified. The coefficient of determination of the model was 0.9674 and the median of the relative fitting error was 4.36%, which shows that the model can well characterize the relationship between the normalized pressure load, the load current and the single spot contact resistance, and provide experimental basis for the resistance calculation of each discrete contact area.

[0129] (3) Under the condition that each branch has a common interface voltage drop, the total current conservation residual is less than the preset tolerance as the convergence criterion. The branch current and contact resistance are solved simultaneously so that the calculation results simultaneously meet the requirements of branch voltage-current relationship and total current conservation, ensuring the consistency of resistance calculation and current distribution in terms of numerical values.

[0130] (4) Analysis Figure 9 and Figure 10 It can be seen that within the load range of 0.03 N to 0.60 N, the total terminal resistance under both current conditions decreases nonlinearly with the increase of contact load. The decrease is faster at low load and then gradually slows down, indicating that increasing the contact load can reduce the resistance, but the magnitude of the resistance reduction gradually decreases with the increase of load.

[0131] (5) Comparison Figure 9 and Figure 10 It can be seen that under the same contact load, the total terminal resistance at 100 mA is lower than that at 1 mA, and the difference is more obvious in the low load stage. This indicates that the influence of current flow conditions on resistance is related to the contact load, and using the load current as the input of the single-spot model can reflect this variation characteristic.

[0132] (6) By calculation, the location, local pressure load, contact resistance and branch current of each discrete contact area can be obtained, the relationship between the difference in local pressure bearing and current distribution can be analyzed, and the influence of surface morphology, assembly position and load current on the overall conductivity can be further compared, providing a basis for the selection of assembly parameters of mating contacts and the optimization of electrical connector structure.

[0133] Example 3:

[0134] A system for predicting the interface resistance of mating contacts based on single-spot electrical contact characteristics includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the computer program is executed, it implements the steps of the method for predicting the interface resistance of mating contacts based on single-spot electrical contact characteristics described in Embodiment 1.

[0135] This embodiment provides a system for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics. The system includes a single-spot testing module, a single-spot electrical contact characteristic model construction module, a contact state acquisition module, a branch current allocation module, and an interface resistance determination module. Each module transmits test data, model parameters, region information, and calculation results through a data interface.

[0136] The single-spot test module includes a probe, a contact clamping and loading device, a pressure load measuring device, a load current application and four-wire voltage measuring device, and a synchronous acquisition device, which are used to execute step S1 and output single-spot contact resistance measurement data under different combinations of pressure load and load current.

[0137] The single-spot electrical contact characteristic model construction module receives contact resistance test data, probe geometric parameters, and contact material parameters. It calculates the initial yield critical pressure load at the test contact, normalizes the measured pressure load, and establishes a single-spot electrical contact characteristic model through parameter identification. This module saves the model coefficients, variable units, and effective current range, and provides a model call interface to the branch current allocation module.

[0138] The contact state acquisition module receives surface topography height data, assembly conditions, and material parameters of the two paired contact components. It obtains discrete contact areas and their local mechanical parameters through surface interferometry and outputs spatial location associated with area number, local pressure load, local equivalent radius of curvature, and normalized pressure load.

[0139] The branch current distribution module maps each discrete contact area to a parallel conductive branch. Based on the normalized pressure load of each discrete contact area, it calls the single-spot electrical contact characteristic model to establish a nonlinear relationship between the contact resistance of each branch and the current of that branch. With the constraint that each branch has the same interface voltage drop and the sum of the currents of each branch equals the given total current, it iteratively solves the current of each branch using the common interface voltage drop as the iterative variable, and outputs the common interface voltage drop, the current of each branch, and the contact resistance of each branch that meet the preset tolerance.

[0140] The interface resistance determination module divides the common interface voltage drop by a given total current and outputs a predicted value for the interface resistance of the mating contacts. For systems with total resistance prediction capabilities for electrical connectors, this module further receives the geometry, resistivity, and series-parallel topology of each conductive component in the electrical connector and calculates the predicted total resistance between the external terminals of the electrical connector.

[0141] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0142] Although this application has been described above with reference to specific embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of this application. In particular, as long as there is no structural conflict, the features in the specific embodiments disclosed in this application can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, this application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics, characterized in that, Includes the following steps: S1. A single contact spot is formed by applying a probe to the contact element. The contact resistance of the single spot is measured under different combinations of pressure load and load current, and a single-spot electrical contact characteristic dataset is constructed. S2. Based on the single-spot electrical contact characteristic dataset obtained in step S1, a single-spot electrical contact characteristic model is established with normalized pressure load and load current as inputs and single-spot contact resistance as output. The normalized pressure load is the ratio of the pressure load to the critical pressure load corresponding to the initial yield at the contact point. S3. Obtain multiple discrete contact areas formed by the contact interface of the mating contact members under a set indentation amount, as well as the local pressure load and local equivalent radius of curvature of each discrete contact area, and calculate the normalized pressure load of each discrete contact area based on the ratio of the local pressure load of each discrete contact area to the critical pressure load corresponding to the initial yield of the discrete contact area. S4. Construct each discrete contact region obtained in step S3 into a parallel conductive branch connected between the paired contact members. Input the normalized pressure load of each discrete contact region and the corresponding branch current to be determined into the single-spot electrical contact characteristic model established in step S2 to determine the nonlinear relationship between the contact resistance of each branch and the branch current. S5. Based on the relationship between the contact resistance and the current of each branch obtained in step S4, and with each branch having the same interface voltage drop and the given total current corresponding to the sum of the currents of each branch as constraints, and with the common interface voltage drop as the iterative variable, solve the current of each branch and the interface voltage drop simultaneously and iteratively; when the absolute value of the total current conservation residual of the difference between the sum of the currents of each branch and the given total current is less than the preset tolerance, output the current of each branch and the common interface voltage drop; otherwise, use a root search algorithm with upper and lower bounds to update the trial value of the interface voltage drop and then solve the current of each branch again. S6. Divide the common interface voltage drop obtained in step S5 by the given total current to output the predicted interface resistance value of the mating contact under the conditions of set pressure and given total current.

2. The method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics according to claim 1, characterized in that, In step S1, the probe and the contact have the same surface material, and the radius of curvature of the probe tip is on the order of micrometers or nanometers, so that there is only a single contact spot between the probe and the contact during the measurement process. The probe is moved along the contact normal direction between the probe and the contact element to achieve the application and continuous adjustment of pressure load; A load current is applied between the probe and the contact, and the contact voltage drop is measured based on the four-wire method. The voltage test line is placed close to the contact to eliminate the influence of the probe and contact body resistance. Synchronous acquisition of pressure load F c Load current I and contact voltage drop U c , and press R c = U c / I Calculate the contact resistance R of a single spot c ; The single-spot electrical contact characteristic dataset is a collection of curves showing the variation of single-spot contact resistance with pressure load under different load currents.

3. The method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics according to claim 1, characterized in that, In step S2, based on the equivalent radius of curvature R, equivalent elastic modulus E, and equivalent hardness H at the single-spot contact point, the critical pressure load F corresponding to the initial yield at the contact point is calculated using the following formula. cri : F cri = (πKH) 3 R 2 / (6E 2 ) Where K is the hardness coefficient, K = 0.454 + 0.41ν, and ν is the Poisson's ratio of the surface material; normalized pressure load. F c This is a pressure load.

4. The method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics according to claim 1, characterized in that, In step S2, the normalized pressure load is used. With load current I as the input variable and single-spot contact resistance R as the input variable... c A single-spot electrical contact characteristic model is constructed for the output variables: Where P3(·,·) is a third-order bivariate polynomial with respect to normalized pressure load and load current, and the parameter to be identified is a mn Let m be the coefficients of the terms of the third-order bivariate polynomial, and m be the normalized pressure load in each term of the third-order bivariate polynomial, where m ranges from 0 to 3 and n = 3 - m. The power exponent of , where n is the power exponent of the load current I in each term of the third-order bivariate polynomial; The normalized pressure load and load current of each group in the single-spot electrical contact characteristic dataset are substituted into a third-order bivariate polynomial about the normalized pressure load and load current. With the goal of minimizing the fitting error between the calculated predicted contact resistance value and the corresponding measured value, each parameter to be identified is identified and determined to obtain the single-spot electrical contact characteristic model. The effective current range of the single-spot electrical contact characteristic model is determined by the range of the load current in the single-spot electrical contact characteristic dataset.

5. The method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics according to claim 1, characterized in that, In step S3, the surface height data of the two contact surfaces of the mating contact parts are obtained and virtual assembly is performed according to the assembly relationship. The local positive geometric interference between the two contact surfaces is calculated according to the set pressing amount, and the interconnected interference nodes are merged into a discrete contact area. For each discrete contact region, local surface fitting is performed on the two contact surfaces, and the equivalent radius of curvature of the discrete contact region is calculated. Based on the surface material parameters and the local equivalent radius of curvature of each discrete contact region, the critical pressure load corresponding to the initial yield of the discrete contact region is calculated, and the local pressure load is calculated in combination with the local indentation of the discrete contact region, thereby obtaining the normalized pressure load of each discrete contact region.

6. The method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics according to claim 1, characterized in that, In step S5, the product of the contact resistance of each branch and the current of that branch is set to equal the trial value V of the interface voltage drop. c Within the effective current range of the single-spot electrical contact characteristic model, solve for the branch current I respectively. i Subtract the given total current I from the sum of the currents in each branch. tot The total current conservation residual Ψ(V) is obtained. c When |Ψ(V) c When the current is less than the preset tolerance ε, the current I of each branch is output. i and common interface voltage drop V c '; Otherwise, a root search algorithm with upper and lower bounds is used in the bounded search interval [V]. min V max After updating the trial value of the interface voltage drop, the solution is recalculated, V. min V is the lower bound of the root search interval for the common interface voltage drop. max This is the upper bound of the root search interval for the common interface voltage drop; The common interface voltage drop V c Divide by the given total current I tot The predicted value R of the interface resistance of the mating contacts is obtained. cp =V c ' / I tot ; reduce the common interface voltage drop V c Divide by the current in each branch I i The contact resistance R of each branch is obtained. c,i = V c ' / I i .

7. The method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics according to claim 1, characterized in that, The mating contacts are disposed in the electrical connector; the predicted interface resistance value R is obtained in step S6. cp Then, the volume resistance R of each conductive component is determined based on the conductive path of the electrical connector. b = ρl / A, where ρ, A, and l are the resistivity, cross-sectional area, and length of the conductive component, respectively; the predicted interface resistance is combined with the volume resistance of each conductive component in series and parallel topology according to the actual current path in the electrical connector to calculate the predicted total resistance R between the external terminals of the electrical connector. s .

8. A system for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed, implements the steps of the method for predicting the interface resistance of paired contacts based on single-spot electrical contact characteristics as described in any one of claims 1-7.

9. The interface resistance prediction system for paired contacts based on single-spot electrical contact characteristics according to claim 8, characterized in that, The system includes a single-spot testing module, which is used to form a single contact spot with the contact element through a probe, and to obtain single-spot contact resistance measurement data under different combinations of pressure loads and different load currents. The single-spot electrical contact characteristic model construction module is used to acquire single-spot contact resistance measurement data, probe geometric parameters, and contact material parameters; calculate the initial yield critical pressure load at the test contact; normalize the measured pressure load; and establish a single-spot electrical contact characteristic model through parameter identification, using the normalized pressure load and load current as inputs and the single-spot contact resistance as outputs. This module saves the model coefficients, variable units, and effective current range, and provides a model calling interface to the branch current allocation module. The contact state acquisition module is used to receive surface topography height data, assembly conditions and material parameters of the two contact parts of the paired contact parts, obtain discrete contact areas and their local mechanical parameters through surface interferometry, and output spatial position associated with area number, local pressure load, local equivalent radius of curvature and normalized pressure load. The branch current distribution module is used to map each discrete contact area into a parallel conductive branch. Based on the normalized pressure load of each discrete contact area, the single-spot electrical contact characteristic model is called to establish the nonlinear relationship between the contact resistance of each branch and the current of that branch. With the constraint that each branch has the same interface voltage drop and the sum of the currents in each branch is equal to the given total current, the common interface voltage drop is used as the iterative variable to solve the current in each branch simultaneously. When the absolute value of the total current conservation residual is less than the preset tolerance, the common interface voltage drop, the current in each branch and the contact resistance of each branch are output. The interface resistance determination module is used to divide the common interface voltage drop by a given total current and output the predicted interface resistance value of the mating contacts.

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