Method for the fastening design of active components of a motor vehicle

Abstract

The invention relates to a method for the fastening design of active components (2) of a motor vehicle, in which at least one active component (2) forming an excitation source can be or is fixed to a structural part (6) of the motor vehicle by at least one fastening (4) forming a connection point, comprising the steps: a. In-situ measurement on the active component (2) by at least one sensor means (8) arranged on an outer surface of the active component (2); b. Virtual point transformation of the results of the in-situ measurement to a virtual point within the active component (2) which includes the position of the ideal load application point of the active component (2); c. inverting a transfer function matrix comprising the sensitivity of the active component (2); d. Determining the in-situ blocked forces / torques of the active component (2) from the in-situ measurement and the inverted transfer function matrix; e. Input or transfer of the determined blocked forces / torques of the active component (2) into a Computer Aided Engineering Simulation (CAE); and f. Determining the blocked forces / torques of at least one fastening (4) by means of the computer-aided engineering simulation.

Description

[0001] The invention relates to a method for the fastening design of active components of a motor vehicle.

[0002] Mounting designs for active components, such as motor vehicles' powertrains, are known from the state of the art to reduce the noise and vibrations caused or generated by the active components. This makes it possible, for example, to reduce the noise and / or the intensity of the noise perceived by a user in the vehicle interior.

[0003] It is known from the state of the art for fastening design to perform so-called in-situ measurements directly on the fastenings in order to indirectly measure the blocked forces / torques present in the fastenings. Sensors are placed on the surfaces of all fastenings to perform the respective in-situ measurement. The measurement result obtained in this way is then transformed to the ideal load application point of the respective fastening using virtual point transformation.

[0004] It has been found to be disadvantageous that, on the one hand, the measurement must be carried out at each fastening or at each fastening point and that the influence of the structural behavior of the active component on the loads at the fastenings forming the connection points cannot be investigated without a new measurement.

[0005] An object of an embodiment of the invention is to propose a method for the fastening design of active components of a motor vehicle, in which the invariant loads at the connection points can be determined in a simplified manner.

[0006] This object is achieved by a method for the fastening design of active components of a motor vehicle, in which at least one active component forming an excitation source can be or is fixed to a structural part of the motor vehicle by at least one fastening forming a connection point, comprising the steps: a. In-situ measurement on the active component by at least one, in particular at least two, sensor means arranged on an outer surface of the active component; b. Virtual point transformation of the results of the in-situ measurement to a virtual point within the active component, which includes the position of the ideal load application point of the active component; c. Inverting a transfer function matrix comprising the sensitivity of the active component; d. Determination of the in-situ blocked forces / torques of the active component from the in-situ measurement, in particular the virtually point-transformed one, and the inverted transfer function matrix; e. Input or transfer of the determined blocked forces / torques of the active component into a computer-aided engineering simulation (CAE), in which the system consisting of the active component forming the excitation source, at least one attachment forming a connection point, and the structural part of the motor vehicle is simulated; and f. Determine the blocked forces / torques of at least one fastening using the computer-aided engineering simulation.

[0007] By performing an in-situ measurement on the active component and by performing this measurement on a virtual point within the active component, which in particular includes the ideal load application point of the active component, the in-situ blocked forces / torques of the active component determined in this way can be used in the simulated computer-aided engineering simulation to determine the invariant loads on the fastenings (i.e. the connection points).

[0008] The "determination" may include a calculation using computer-aided engineering simulation. The virtual point may include an ideal load application point or another suitable point within the active component, such as the center of gravity of the active component.

[0009] An in-situ measurement is defined as a measurement in the assembled state. By performing an in-situ measurement on the active component and applying the virtual point transformation to the virtual point of the active component, the invariant loads can be determined at the virtual point of the excitation source, namely the active component.

[0010] For computer-aided engineering simulation, a simplified rigid-body principle can be assumed, in which the active component is assumed to be essentially rigid. Each attachment can serve as an attachment point.

[0011] The method according to the invention eliminates the need for in-situ measurements at all attachment points and instead allows measurements to be taken at a single point in the system consisting of the active component, attachments, and structural part. From the measurement result, the blocked forces / torques of the active component, the blocked forces / torques at the individual attachments and / or the structural part of the vehicle are determined, in particular calculated, using computer-aided engineering simulation.

[0012] In principle, it is conceivable that the position and orientation of the at least one sensor means and the virtual point within the active component are already known, in particular stored in a computing unit. Alternatively or additionally to this, an embodiment of the method can be characterized by a precise detection of the position and orientation of the at least one sensor means by at least one measuring device and storing the position of the at least one sensor means in a computing unit and / or by determining the virtual point forming the ideal load application point within the active component by the computer-aided engineering simulation or by a CAD model of the active component in the computing unit, in particular for carrying out the virtual point transformation of the in-situ measurement to the virtual point within the active component.

[0013] If the transfer function matrix is ​​not known, it can be determined in one embodiment by determining the transfer function matrix, wherein the physical system of active component, attachment and structural part comprises at least one input point and at least one response point, with the steps: a. receiving in-situ measurement of input data for at least one excitation point and / or response data for at least one indicator point of the physical system by the at least one sensor means; b. Receiving at least one system response function between the at least one excitation point and the at least one indicator point by the at least one sensor means; and c. Applying at least one parametric model, in particular a transfer function from the excitation point to the indicator point, which characterises at least one load on the physical system as a function of the input data.

[0014] This makes it possible to determine the transfer function matrix by applying a given or known load to the physical system.

[0015] The transfer function matrix remains constant for the physical system.

[0016] In this case, it proves to be particularly advantageous if the load for determining the transfer function matrix by in situ measurement by the at least one sensor means comprises a known or predetermined unit force with which the active component is acted upon.

[0017] If the load comprises a known or predetermined unit force, the transfer function matrix of the physical system can be easily determined.

[0018] If, in the method according to the invention, acceleration forces / torques are detected during operation of the active component by means of in-situ measurement by the at least one sensor means, the blocked forces / torques of the active component can be determined in a simple manner using the measured accelerations and the transfer function matrix that is constant for the physical system.

[0019] The sensor means can measure various physical properties. It is advantageous if the at least one sensor means comprises an accelerometer and if the in-situ measurement acquired by the at least one sensor means comprises an acceleration measurement.

[0020] If an acceleration measurement is carried out by at least one sensor means, the blocked force can be determined in a simple manner.

[0021] The transfer function matrix must be overdetermined with respect to the number of forces / moments to be determined. In this case, it is advantageous if the acceleration measurement is three-dimensional and includes three mutually perpendicular acceleration vectors.

[0022] In order to further improve the result of the in-situ measurement, it proves to be advantageous if the in-situ measurement on the active component is carried out by at least three sensor means arranged on the outer surface of the active component and if the virtual point transformation of the in-situ measurement to the virtual point within the active component comprises the in-situ measurements of the at least three sensor means.

[0023] The blocked forces / torques of the active component can be easily determined if the determination of the in-situ blocked forces / torques of the active component involves a product of the measured accelerations of the in-situ measurement and the inverted transfer function matrix.

[0024] Furthermore, it is conceivable that the process could be modified. This proves particularly advantageous when the blocked forces / torques of the active component have been determined and the design of the fastening system needs to be further optimized.

[0025] Such embodiments of the method are characterized by a modification of the active component(s) stored in the Computer Aided Engineering Simulation (CAE), the at least one fastening and / or the structural part and input of the determined blocked forces / torques of the active component into the modified Computer Aided Engineering Simulation (CAE), wherein the determination of the blocked forces / torques of the at least one fastening is carried out by the modified Computer Aided Engineering Simulation.

[0026] In such a case, it proves to be particularly advantageous if the modification comprises a change in the geometry of the active component(s) stored in the Computer Aided Engineering Simulation (CAE), the at least one fastening and / or the structural part.

[0027] The modification makes it possible to modify the individual components of the physical system and, given the known blocked forces / torques of the active component, to determine the resulting change in the blocked forces / torques of at least one fastening element. This eliminates the need for complex measurements on the fastening elements and allows for the exclusive use of computer-aided engineering simulation.

[0028] In embodiments of the method and the physical system, the active component can be fixed to a structural part of the motor vehicle via at least three fastenings, each forming a connection point.

[0029] Further features, details and advantages of the invention emerge from the appended patent claims, from the drawings and the following description of a preferred embodiment of the method.

[0030] The drawing shows: Fig. 1 A schematic flow diagram of a method according to the invention; Fig. 2 A perspective front view of a system consisting of an active component, a fastening element and a structural part; Fig. 3 A schematic representation of an in-situ measurement according to the method according to Fig. 1.

[0031] Fig. 1 shows a schematic flow diagram of a method according to the invention as well as possible method steps for modifying the method.

[0032] To illustrate the procedure, the diagrams are shown in Fig. 2 and Fig. 3 was used. Fig. Figure 2 shows a physical system consisting of an active component 2, which forms an excitation source. The active component 2 is secured to a structural part 6 of the motor vehicle (not explicitly shown in the figures) via several attachments 4. The attachments 4 form connection points.

[0033] In the embodiment shown in the figures, at least three sensor means 8 are arranged on the active component 2.

[0034] The representation according to Fig. 1 shows a schematic flow diagram of a method for the fastening design of active components 2 of a motor vehicle, in which at least one active component 2 forming an excitation source is fixed to a structural part 6 of the motor vehicle by at least one fastening 4 forming a connection point.

[0035] In a first step 100, an in-situ measurement is performed on the active component 2 by the sensor means 8. The sensor means 8 are arranged on an outer surface of the active component 2.

[0036] In a subsequent step 101, a virtual point transformation of the results of the in-situ measurement is performed to a virtual point within the active component 2. The virtual point within the active component 2 includes the position of the ideal load application point of the active component 2.

[0037] In a further step 102, a transfer function matrix comprising the sensitivity of the active component 2 is inverted.

[0038] In a subsequent step 103, the in-situ blocked forces / torques of the active component 2 are determined from the in-situ measurement and the inverted transfer function matrix.

[0039] The now obtained blocked forces / torques of the active component 2 can be entered or imported into a computer-aided engineering simulation in a step 104 for the stored physical system consisting of the active component 2, the fastenings 4, and the structural part 6. The computer-aided engineering simulation simulates the system consisting of the excitation source-forming active component 2, the fastening 4 forming at least one connection point, and the structural part 6 of the motor vehicle.

[0040] In a subsequent step 105, the blocked forces / torques of at least one fastening 4 are determined from the computer-aided engineering simulation.

[0041] Alternatively, the method can be modified after step 103. The determined blocked forces / torques of the active component 2 are entered into or imported into a modified computer-aided engineering simulation. This simulation includes modifications, such as geometry changes, of the active component 2 stored in the computer-aided engineering simulation, which includes at least one fastening element 4 and / or the structural part 6. The geometry change can include, for example, the addition of stiffeners or a housing modification of the active component 2.

[0042] In a subsequent step 105', the blocked forces / torques of at least one fastening 4 are then determined on the basis of the modified computer-aided engineering simulation.

[0043] Fig. 3 shows a schematic representation of steps 100 and 101. Fig.3 shows that the sensor means 8 are arranged on an outer surface of the active component 2. The results of the in-situ measurement determined there, which may include, for example, an acceleration measurement, are virtually point-transformed to a virtual point within the active component 2 by means of virtual point transformation. The virtual point within the active component 2 can be calculated in advance using a CAD program and include the position of the ideal load application point of the active component 2.

[0044] The features of the invention disclosed in the above description, in the claims and in the drawings can be essential both individually and in any combination in the realization of the invention in its various embodiments within the scope of the following claims. List of reference symbols 2 active components 4 Fastening 6 Structural part 8 Sensor means 100-105 104' and 105' process steps

Claims

[1] Method for the fastening design of active components (2) of a motor vehicle, in which at least one active component (2) forming an excitation source can be or is fixed to a structural part (6) of the motor vehicle by at least one fastening (4) forming a connection point, comprising the steps: a. In-situ measurement on the active component (2) by at least one, in particular at least two, sensor means (8) arranged on an outer surface of the active component (2); b. Virtual point transformation of the results of the in-situ measurement to a virtual point within the active component (2) which includes the position of the ideal load application point of the active component (2); c. inverting a transfer function matrix comprising the sensitivity of the active component (2); d. Determining the in-situ blocked forces / torques of the active component (2) from the in-situ measurement, in particular virtually point-transformed, and the inverted transfer function matrix; e. Input or transfer of the determined blocked forces / torques of the active component (2) into a computer-aided engineering simulation (CAE), in which the system comprising the active component (2) forming the excitation source, at least one fastening (4) forming a connection point, and the structural part (6) of the motor vehicle is simulated; and f. Determining the blocked forces / torques of at least one fastening (4) by means of the computer-aided engineering simulation. [2] Method according to claim 1, characterized bya precise detection of the position and orientation of the at least one sensor means (8) by at least one measuring device and storing the position of the at least one sensor means (8) in a computing unit and / or by determining the virtual point forming the ideal load application point within the active component (2) by the computer-aided engineering simulation or by a CAD model of the active component (2) in the computing unit, in particular for carrying out the virtual point transformation of the in-situ measurement to the virtual point within the active component (2). [3] Method according to claim 1 or 2, characterized by determining the transfer function matrix, wherein the physical system comprising active component (2), fastening (4) and structural part (6) comprises at least one input point and at least one response point, with the steps: a. receiving in-situ measurement of input data for at least one excitation point and / or response data for at least one indicator point of the physical system by the at least one sensor means (8); b. receiving at least one system response function between the at least one excitation point and the at least one indicator point by the at least one sensor means (8); and c. Applying at least one parametric model, in particular a transfer function from the excitation point to the indicator point, which characterises at least one load on the physical system as a function of the input data. [4] Method according to claim 3, characterized by that the load for determining the transfer function matrix by in situ measurement by the at least one sensor means (8) comprises a known or predetermined unit force with which the active component (2) is acted upon. [5] Method according to one of the preceding claims, characterized by that the at least one sensor means (8) comprises an accelerometer and that the in-situ measurement detected by the at least one sensor means (8) comprises an acceleration measurement. [6] Method according to claim 5, characterized by that the acceleration measurement is three-dimensional and comprises three acceleration vectors that are perpendicular to each other. [7] Method according to one of the preceding claims, characterized by that the in-situ measurement on the active component (2) is carried out by at least three sensor means (8) which are arranged on the outer surface of the active component (2), and that the virtual point transformation of the in-situ measurement to the virtual point within the active component (2) comprises the in-situ measurements of the at least three sensor means (8). [8] Method according to one of the preceding claims, characterized bythat the determination of the in-situ blocked forces / torques of the active component (2) comprises a product of the measured accelerations of the in-situ measurement and the inverted transfer function matrix. [9] Method according to one of the preceding claims, characterized by a modification of the active component (2), the at least one fastening (4) and / or the structural part (6) stored in the computer-aided engineering simulation (CAE) and input of the determined blocked forces / torques of the active component (2) into the modified computer-aided engineering simulation (CAE), wherein the determination of the blocked forces / torques of the at least one fastening (4) is carried out by the modified computer-aided engineering simulation. [10] Method according to claim 9, characterized bythat the modification comprises a change in the geometry of the active component (2) stored in the Computer Aided Engineering Simulation (CAE), the at least one fastening (4) and / or the structural part (6).

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