Aircraft part arc detection device and stability evaluation method thereof

Abstract

The invention provides an aircraft part arc detection device and a stability evaluation method thereof, the detection device comprises a dial indicator, a fixing screw and a detection frame, the detection frame is of a three-jaw equally-divided structure, a through hole through which the fixing screw can penetrate is formed in the detection frame, and the detection frame is fixed in the middle of a measuring rod of the dial indicator through the fixing screw; according to the detection method, the surface hole depth of the measured convex arc or concave arc and the depth of the butt joint gap can be obtained through the measuring dial indicator according to the bowstring method measuring principle. The device is a handheld arc surface detection device, is convenient to operate, is easy for on-site online operation, is higher in measurement precision, solves the problem of poor measurement precision of a hook ruler used on site, and can be matched with a measurement needle to perform high-precision measurement on small holes, skin butt joint depth and scratch depth of the skin.

Description

Technical Field

[0001] The invention relates to the field of measurement technology, and in particular to an arc detection device for aircraft parts and a stability evaluation method thereof. Background Art

[0002] In the manufacturing and testing process of aircraft parts, we often encounter the problem of arc surface dimensions that cannot be directly measured, such as the hole depth of convex or concave arc surface, the depth of butt joint gap, the depth of scratches, etc. The measurement of these arc parts requires the use of hook gauges, depth gauges, feeler gauges and other measuring tools for detection. Especially when the hole diameter is smaller than the diameter of the hook gauge, other auxiliary tools are usually required for detection and measurement. This detection method is time-consuming and labor-intensive, with low detection efficiency and low accuracy. Especially for mass-produced arc parts, the use of traditional detection methods seriously affects the on-time delivery of products.

[0003] There is an urgent need to provide an evaluation method for the stability of an arc surface detection device that can be directly used on the production site. The detection device developed by this method has high measurement accuracy, large range, simple structure, small size, and low cost, so as to make up for the shortcomings of the current arc surface detection and measurement methods. Summary of the invention

[0004] Purpose of the invention: In order to solve the technical problems that there is no direct detection method for the hole depth on the arc surface, especially the depth of small holes, during the processing and inspection of aircraft parts, and indirect measurement or auxiliary measurement methods are usually used, resulting in low measurement accuracy, and when detecting the scratch and gap depth in the arc area, the measurement process mostly adopts qualitative measurement methods, and the depth of the scratch cannot be accurately measured. The present invention provides an aircraft part arc surface detection device based on mechanics and a stability evaluation method thereof, including a dial indicator, fixing screws, and a detection frame. The detection frame is a three-claw equally divided structure, and a through hole is provided in the middle of the fixing screw, and the detection frame is fixed to the middle of the measuring rod of the dial indicator by the fixing screw.

[0005] In a first aspect, the present application provides an arc detection device for aircraft parts, the device comprising:

[0006] Testing rack;

[0007] A measuring claw, mounted at the bottom of the detection frame;

[0008] A measuring column, mounted on the upper part of the detection frame;

[0009] A dial indicator is arranged on the measuring column.

[0010] In a second aspect, the present application also provides a method for evaluating the stability of an arc detection device for aircraft parts, the method comprising the following steps:

[0011] Step 1: Establish a reasonably simplified finite element model of the arc detection device for aircraft parts;

[0012] Step 2: Parametric modeling of the measuring claw considering structural stability;

[0013] Step 3: Finite element simulation calculation;

[0014] Step 4: Establish the basis for stability judgment.

[0015] Preferably, the step 1 is to establish a reasonably simplified finite element model of the arc detection device for aircraft parts, and the specific process is as follows:

[0016] A three-dimensional geometric model of an aircraft parts arc detection device is established using CAD software, wherein all parts except the dial indicator, measuring column, detection frame, and measuring claws in the aircraft parts arc detection device model are deleted to form a simplified model, and the simplified model is ensured to have the same length, width, and height as the actual aircraft parts arc detection device.

[0017] A measurement object model is established below the simplified model, and the length and width of the measurement object model are not less than the length and width outer dimensions of the actual aircraft part arc detection device.

[0018] Preferably, the parametric modeling of the measuring jaws considering the structural stability in step 2 comprises the following steps:

[0019] On the basis of step 1, the geometric shape and size of the measuring claws are kept unchanged, and only the number of measuring claws is increased, and the three-dimensional geometric models of arc detection devices for aircraft parts with different numbers of measuring claws are established respectively;

[0020] For the three-dimensional geometric model of the arc detection device for aircraft parts with different numbers of measuring claws, the geometric shape is kept unchanged and only its height is changed. 1 mm is added to the original measuring claw height at a time to establish the three-dimensional geometric model of the arc detection device for aircraft parts with different measuring claw heights.

[0021] Preferably, the finite element simulation calculation in step 4 includes the following steps:

[0022] Set Young's modulus, Poisson's ratio and density for each physical object such as dial indicator, measuring column, testing frame, measuring claw and measuring object model;

[0023] Boundary condition setting;

[0024] Meshing;

[0025] The statics module in the finite element software is used to solve the displacement field and stress field results of the three-dimensional geometric model of the arc detection device of aircraft parts during use.

[0026] Preferably, the boundary condition setting includes:

[0027] Set constraints to limit 6 degrees of freedom at the bottom of the measured object model; the friction between the measuring claw and the measured object model is used as a support force to maintain stability, and the friction coefficient between the measuring claw and the three-dimensional geometric model of the measured object model is input;

[0028] Preferably, the grid division includes:

[0029] The maximum length, width and height of a single grid in the three-dimensional geometric model of the arc detection device for aircraft parts and the measurement object model shall not exceed 10% of the length, width and height of the parts.

[0030] Preferably, the step 4 of establishing a basis for determining stability comprises the following steps:

[0031] 4-1 The normal interaction force T between the probe claw and the measured object model in the aircraft parts arc detection device model is obtained by integrating the contact stress through formula 1: z

[0032] T z =-∫σ z dA1

[0033] Among them, σ z is the stress component of each unit in the vertical direction, A is the contact area; the normal interaction force T is obtained by integrating over the entire contact area. z ;

[0034] 4-2 Repeat step 4-1 to find the normal interaction force T between the i-th measuring claw and the measured object model. z,i , record the maximum value of the normal interaction force T z,max and minimum value T z,min ;

[0035] 4-3 Establish the basis for determining stability based on formula 2:

[0036]

[0037] Among them, ε is the stable use probability of the aircraft parts arc detection device model; when the calculation result of ε is equal to 100%, it means that the aircraft parts arc detection device has good stability during use; when the calculation result of ε is less than or equal to the design value, it is necessary to modify the number and height of the measuring claws in the simplified model, and repeat step 2 until the calculated stable use probability ε meets the actual needs.

[0038] Beneficial effects of the present invention:

[0039] The present invention is a handheld arc surface detection device, which is easy to operate and easy to operate on-site online. In the detection of mass-produced parts, it replaces traditional measurement methods such as feeler gauges and hook gauges. A quick arc surface detection device based on a dial indicator greatly improves the detection efficiency and accuracy. The present invention has a stable structure, so that each part is evenly stressed during the measurement process, is durable and not easy to damage. Compared with the existing arc detection technology, this structure improves the stability and accuracy of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of a finite element model of an arc detection device for aircraft parts in step 1 of the present invention;

[0041] Figure 2 A schematic diagram of a three-dimensional geometric model of an aircraft parts arc detection device with different numbers of measuring claws in step 2 of the present invention;

[0042] Figure 3 This is a schematic diagram of the mesh division result in step three of the present invention;

[0043] Figure 4 This is a schematic diagram of the result of calculating the normal interaction force in step three of the present invention;

[0044] Figure 5 This is a schematic diagram of the stable use probability of the aircraft parts arc detection device model with different numbers of measuring claws and different measuring claw heights calculated in step 4 of the present invention.

[0045] Explanation of numbers in the figure: 1. dial indicator; 2. measuring column; 3. detection frame; 4. measuring claw; 5. measuring object. DETAILED DESCRIPTION

[0046] The present invention provides an arc detection device for aircraft parts and a stability evaluation method thereof. The detection device includes a dial indicator, a fixing screw, and a detection frame. The detection frame is a three-claw equally divided structure, wherein a through hole through which the fixing screw can pass is provided, and the detection frame is fixed to the middle of the measuring rod of the dial indicator by the fixing screw; the detection method uses the bowstring method measurement principle to measure the dial indicator, and can obtain the hole depth and the butt joint gap depth of the measured convex arc or concave arc surface. The present invention is a handheld arc surface detection device, which is easy to operate and easy to operate online on site, and has high measurement accuracy, replacing the problem of poor measurement accuracy using a hook ruler on site. At the same time, with the measurement needle, it can perform high-precision measurement of smaller holes in the skin, the butt joint depth of the skin, and the scratch depth.

[0047] See also Figure 1-Figure 5 The technical solution of the present invention is: a method for evaluating the stability of an arc detection device for aircraft parts based on mechanics, comprising the following steps:

[0048] Step 1: Establish a reasonably simplified finite element model of the arc detection device for aircraft parts;

[0049] Step 2: Parametric modeling of the measuring claw considering structural stability;

[0050] Step 3: Finite element simulation calculation;

[0051] Step 4: Establish the basis for stability judgment;

[0052] Among them, step 1 is to establish a reasonably simplified finite element model of the arc detection device for aircraft parts. The specific process is as follows:

[0053] 1-1 Use CATIA 2018 software to establish a three-dimensional geometric model of an aircraft parts arc detection device, in which all parts except the dial indicator 1, measuring column 2, detection frame 3, and measuring claw 4 in the aircraft parts arc detection device model are deleted as a simplified model to ensure that the simplified model has the same length, width, and height as the actual aircraft parts arc detection device. Figure 1 As shown;

[0054] 1-2 A measurement object model 5 is established below the simplified model, and the length and width of the measurement object model are not less than the length and width outer dimensions of the actual aircraft parts arc detection device. In this embodiment, the length, width and height of the measurement object model are 200 mm, 200 mm and 3 mm respectively.

[0055] The parametric modeling of the measuring jaws considering the structural stability in step 2 includes the following steps:

[0056] 2-1 Based on step 1, the geometric shape and size of the measuring claws are kept unchanged, and only the number of measuring claws is increased from 2 to 7. The three-dimensional geometric models of the arc detection device for aircraft parts with different numbers of measuring claws are established respectively, as shown in FIG. Figure 2 As shown;

[0057] 2-2 For the three-dimensional geometric model of the arc detection device for aircraft parts with different numbers of measuring claws, the geometric shape is kept unchanged and only its height is changed. 1mm is added to the original measuring claw height of 16mm at a time, and the three-dimensional geometric model of the arc detection device for aircraft parts with different measuring claw heights of 15mm and 16mm is established.

[0058] Among them, the finite element simulation calculation in step three includes the following steps:

[0059] 3-1 Set Young's modulus, Poisson's ratio and density for each object of the dial gauge, measuring column, detection frame, measuring claw and measurement object model; in this embodiment, the Young's modulus of the dial gauge 1, measuring column 2, detection frame 3 and measuring claw 4 are uniformly set to 70 GPa and Poisson's ratio is 0.33. The density is 2.63×10 -9 t / mm3 The Young's modulus of the measured model 5 is 210×10 5 GPa, Poisson's ratio is 0.30, and density is 4×10 -9 t / mm 3 ;

[0060] 3-2 Boundary condition setting: set constraints to limit 6 degrees of freedom at the bottom of the measured object model 5; the friction between the measuring claw 4 and the measured object model 5 is used as a support force to maintain stability, and the friction coefficient between the measuring claw 4 and the measured object model 5 is input as μ=0.2;

[0061] 3-3 Grid division: The maximum length, width and height of a single grid in the three-dimensional geometric model of the arc detection device for aircraft parts and the measurement object model shall not exceed 10% of the length, width and height of the part, such as Figure 3 As shown;

[0062] 3-4 The statics module in the finite element software AQBAQUS 6.14 is used to solve and calculate the displacement field and stress field results of the three-dimensional geometric model of the arc detection device of aircraft parts during use, such as Figure 4 shown.

[0063] Among them, step three is to establish the basis for stability judgment, including the following steps:

[0064] 4-1 The normal interaction force T between the probe claw and the measured object model in the aircraft parts arc detection device model is obtained by integrating the contact stress through formula 1: z

[0065] T z =-∫σ z dA1

[0066] Among them, σ z is the stress component of each unit along the vertical direction, i.e., the CPRESS compressive stress result, and A is the contact area of ​​45 mm 2 , the normal interaction force T is obtained by accumulating each unit and integrating it over the entire contact area. z =1.05N;

[0067] 4-2 Repeat step 4-1 and find that the normal interaction forces between the three measuring claws and the measured object model are 1.08N, 1.05N and 1.05N respectively, and record the maximum value of the normal interaction force T z,max =1.08N and minimum value T z,min =1.05N;

[0068] 4-3 Establish the basis for determining stability based on formula 2:

[0069]

[0070] Among them, ε is the stable use probability of the aircraft parts arc detection device model. In this embodiment, the stable use probability ε when the measuring claw height is 15mm and 16mm is 97.6% and 96.3% respectively, indicating that the aircraft parts arc detection device has good stability during use. When the calculated result of ε is less than or equal to the design value, it is necessary to increase the number of measuring claws or reduce the height of the measuring claws in the simplified model, and repeat step 2 until the calculated stable use probability ε meets the actual needs, such as Figure 5 shown.

[0071] The present invention provides a circular arc radius detection device based on a dial indicator, such as Figure 1 As shown, it consists of a dial indicator, a detection frame, a measuring claw and a measuring column. The specific implementation steps are as follows:

[0072] (1) Assembly and calibration. Vertically pass the measuring rod of the dial indicator through the through hole in the middle of the test frame, and use screws to lock the test frame and the dial indicator to assemble the measuring device. Place the measuring rod and the measuring column of the dial indicator on the calibration platform at the same time, and turn the dial of the dial indicator so that the pointer coincides with the zero position.

[0073] (2) Measure the depth of the hole on the arc surface. Place the dial indicator measuring column at the hole mouth, align and zero the dial indicator measuring rod at the hole mouth, and insert the measuring rod and dial indicator into the bottom of the hole through the measuring frame (the depth measurement of different deep holes and small holes can be achieved by changing the diameter of the measuring head and the length of the measuring rod), and measure the hole diameter depth of the arc surface by reading the meter.

[0074] (3) Measure the depth of scratches and gaps on the arc surface. Distribute the dial indicator measuring columns on both sides of the scratch, align and zero the dial indicator measuring rod on the arc surface, and insert the measuring rod and dial indicator through the measuring frame to the bottom of the scratch (the diameter of the measuring head can be changed to achieve the measurement of scratches of different widths), and measure the depth of the scratch on the arc surface by reading the meter.

Claims

1. An arc detection device for aircraft parts, characterized in that: The device comprises: Testing rack; A measuring claw, mounted at the bottom of the detection frame; A measuring column, mounted on the upper part of the detection frame; A dial indicator is arranged on the measuring column.

2. A method for evaluating the stability of an arc detection device for aircraft parts, characterized in that: The method comprises the following steps: Step 1: Establish a reasonably simplified finite element model of the arc detection device for aircraft parts; Step 2: Parametric modeling of the measuring claw considering structural stability; Step 3: Finite element simulation calculation; Step 4: Establish the basis for stability judgment.

3. The method according to claim 2, characterized in that The step 1 is to establish a reasonably simplified finite element model of the arc detection device for aircraft parts. The specific process is as follows: A three-dimensional geometric model of an aircraft parts arc detection device is established using CAD software, wherein all parts except the dial indicator, measuring column, detection frame, and measuring claws in the aircraft parts arc detection device model are deleted to form a simplified model, and the simplified model is ensured to have the same length, width, and height as the actual aircraft parts arc detection device. A measurement object model is established below the simplified model, and the length and width of the measurement object model are not less than the length and width outer dimensions of the actual aircraft part arc detection device.

4. The method according to claim 3, characterized in that The parametric modeling of the measuring jaws considering the structural stability in step 2 includes the following steps: On the basis of step 1, the geometric shape and size of the measuring claws are kept unchanged, and only the number of measuring claws is increased, and the three-dimensional geometric models of arc detection devices for aircraft parts with different numbers of measuring claws are established respectively; For the three-dimensional geometric model of the arc detection device for aircraft parts with different numbers of measuring claws, the geometric shape is kept unchanged and only its height is changed. 1 mm is added to the original measuring claw height at a time to establish the three-dimensional geometric model of the arc detection device for aircraft parts with different measuring claw heights.

5. The method according to claim 4, characterized in that The finite element simulation calculation in step 4 includes the following steps: Set Young's modulus, Poisson's ratio and density for each physical object such as dial indicator, measuring column, testing frame, measuring claw and measuring object model; Boundary condition setting; Meshing; The statics module in the finite element software is used to solve the displacement field and stress field results of the three-dimensional geometric model of the arc detection device of aircraft parts during use.

6. The method according to claim 5, characterized in that The boundary condition setting includes: Constraints are set at the bottom of the measured object model to limit 6 degrees of freedom; the friction between the measuring claw and the measured object model is used as a support force to maintain stability, and the friction coefficient between the measuring claw and the three-dimensional geometric model of the measured object model is input.

7. The method according to claim 6, characterized in that The grid division includes: The maximum length, width and height of a single grid in the three-dimensional geometric model of the arc detection device for aircraft parts and the measurement object model shall not exceed 10% of the length, width and height of the parts.

8. The method according to claim 2, characterized in that: The step 4 of establishing a stability judgment basis includes the following steps: 4-1 The normal interaction force T between the probe claw and the measured object model in the aircraft parts arc detection device model is obtained by integrating the contact stress through formula 1: z T z =-∫σ z dA 1 Among them, σ z is the stress component of each unit in the vertical direction, A is the contact area; the normal interaction force T is obtained by integrating over the entire contact area. z ; 4-2 Repeat step 4-1 to find the normal interaction force T between the i-th measuring claw and the measured object model. z,i , record the maximum value of the normal interaction force T z,max and minimum value T z,min ; 4-3 Establish the basis for determining stability based on formula 2: Among them, ε is the stable use probability of the aircraft parts arc detection device model; when the calculation result of ε is equal to 100%, it means that the aircraft parts arc detection device has good stability during use; when the calculation result of ε is less than or equal to the design value, it is necessary to modify the number and height of the measuring claws in the simplified model, and repeat step 2 until the calculated stable use probability ε meets the actual needs.

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