EP3535574A1

EP3535574A1 - Moulded part made from fibre composite

Info

Publication number: EP3535574A1
Application number: EP17780406.9A
Authority: EP
Inventors: Uwe Lauschke
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2016-11-02
Filing date: 2017-10-06
Publication date: 2019-09-11
Also published as: CN109906378A; DE102016221469A1; WO2018082861A1

Abstract

The invention relates to a moulded part comprising a layer made from a fiber composite which extends along a surface, and a scanning device fixed to the moulded part, which is designed to determine physical properties of the moulded part on the area where the scanning device is applied.

Description

Molded part made of fiber composite material

The invention relates to a molded part made of fiber composite material. In particular, the invention relates to the verification of a physical property of the molding.

A rail vehicle, such as a locomotive, a railbus or a railroad car, includes a chassis and a fairing. The cladding can be used in particular in the front area in order to achieve an aerodynamically favorable shape, to ensure impact protection or to protect elements of the vehicle from environmental influences such as moisture, ice or dirt. The cladding may comprise a molded part formed with a fiber composite material. Other molded parts can be on an outer skin, on the front end, a

Bow nose, a bow door or a roof part of the vehicle can be used. A fiber composite is formed of fibers embedded in a matrix. A molded article comprising a fiber composite material can combine low weight and high strength. In addition, the molded part can be inexpensive, durable and resistant to chemicals and offer a superior variety of shapes.

WO 2010/029 188 A1 teaches a vehicle head structure, in particular a rail vehicle, wherein the vehicle head structure is completely formed with structural elements of fiber composite materials.

DE 10 2006 018 461 A1 proposes to equip a molded part made of fiber-reinforced plastic with at least one RFID transponder in order to detect a counterfeiting of the molded part.

In order to check a molded part with a fiber composite material for damage, for example due to stone chipping or an accident, usually an external device is needed, which is operated by a trained person. In addition, accurate knowledge of the molded part may be required to distinguish, for example, a laminated stiffening element from damage. The investigation can be time-consuming and require disassembly of the molding or other part of the vehicle.

DE 10 2007 014 696 B3 relates to a technique for determining structural information of materials, in particular on a lightweight structure. For this purpose, piezoelectric sensors are distributed over the surface of the material to be tested and waves in the surface direction are exchanged between the sensors.

However, this technique requires a customized to the respective component preparation of measured values. An object underlying the present invention is to provide an improved technique for inspecting a molded article with a fiber composite for damage. The present invention solves this problem by means of the subject matters of the independent claims. Subclaims give preferred embodiments again.

A molded article comprises a layer of fiber composite extending along a surface and a scanner attached to the mold configured to determine a physical property of the molded article at a mounting location of the scanner.

By determining the physical property punctually at the mounting location, it is not necessary to set the determined physical property in relation to a shape of the molding in the plane direction. A calibration or mutual tuning of scanning devices, which in

Surface direction are spaced apart, does not have to be performed. A processing effort for the determination of damage can thereby be significantly reduced. Based on the specific physical property, the state of the

Shaped be determined in a simple and understandable manner. As a result, the molded part can remain at its installation location while a check is taking place. The review can be done quickly and with little effort. In one embodiment, the check may even be performed during the operation of a device to which the molding is attached. The device may for example be a rail vehicle may include, for example, a fairing, an outer skin, a front end, a nose, a roof part, a front door or other element on the vehicle. To check the molding neither a mobile scanner nor a trained personnel to handle it is required. An operator of the apparatus can perform a check of the molding itself without, for example, using an external service.

It is particularly preferred that a plurality of scanning devices is arranged distributed in the planar direction on the layer. Often, the molded article has a substantially constant thickness in a direction perpendicular to the layer. The physical properties determined by means of the scanning devices can then be comparable with one another, in particular between adjacent scanning devices. However, for the proposed technique, the molding may also have a varying thickness. To determine a

Damage can also be analyzed by changing the physical parameter at one point over time. Due to the lack of correlation between the scans of the various scanners, the determination of the damage can be performed in a simplified form.

The scanning devices may preferably be attached to locations of the molding which is improved in terms of the condition of the molding or for which a likelihood of damage is increased. For example, a relative distance between scanners may be in a range of about 20 to 120 mm. In this case, the scanning devices can be arranged regularly, for example in the form of a matrix or in a grid in the manner of a honeycomb, or irregularly according to the scattering principle. It is preferred that a maximum distance of any point of the molding from a nearest scanning device does not exceed a predetermined value. The scanning devices may be wired in a first variant, wherein a power or data line with the molding and in particular with the layer may be firmly connected. In another variant, the scanning devices are wireless and an energy or data connection can be made by means of electromagnetic waves. In particular, a known wireless technology such as RFID or

Bluetooth can be used. In all embodiments it is preferred that a standardized interface is formed over which the particular physical properties are provided. This interface can be defined both physically and logically. It is further preferred that the physical property along a

Direction is determined perpendicular to the layer. In particular, if the layer is of substantially constant thickness, certain physical properties may be put in context at closely spaced locations. A precise knowledge of the mounting locations is not required because the specific physical property is not affected by the distance of the scanning devices to each other. However, measurements in the thickness direction may be made when the molded article has a thickness varying over the surface.

The physical property is preferably dependent on damage to the molded part. For example, the physical property may include a thermal conductivity, a conductivity or an echo behavior for a wave, in particular an acoustic or electromagnetic wave, an electrical conductivity, capacitance or inductance. If the component is damaged, the physical property changes in the region of the damage, so that on the basis of the physical signal, a check of the component for damage can be performed. The damage may include aging, moisture damage, radiation damage, crack or microcrack, hole or breakage. The functionality of the molded part can be determined in particular improved on a critical component.

The layer can be connected to another layer in a planar manner and the damage can include a detachment of the two layers from one another. Such damage is also called delamination or delamination, and may occur, for example, between different layers of fiber composites. In a further embodiment, the further layer comprises a carrier structure, which may be designed in particular as a foam core. The molded part can thus be designed as a one-sided or two-sided sandwich construction. By conventional methods, partial delamination of the layer from the support structure is very difficult be detectable. By means of the at least one scanning device on the described molding detachment can be reliably detected already at a relatively early stage. Different physical properties of the molded part can be checked. In one embodiment, the scanning device comprises a transmitter for a wave propagating in the molding and a receiver which is adapted to scan a reflection of the wave. In particular, the shaft can be mechanical, which also refers to structure-borne sound. The transmitter and the receiver may coincide and, for example, in

Formed a piezoelectric element. In other embodiments, an electromagnetic wave may also be used, for example in the radar or X-ray region. In still another embodiment, ductility for heat may also be determined. It is generally preferred that the physical properties of the molding in the thickness direction, ie perpendicular to

Surface direction, to be checked. The scanning device can be designed in particular in one piece. An analysis of the physical properties may be allowed without having to match two or more elements separately attached to the molding.

In yet another embodiment, the scanning device comprises a circuit which flows through a portion of the molding in a direction perpendicular to the layer. In a first variant, an electrically conductive element is provided for this purpose at this point, in a second variant, the current can flow directly through the molded part. This variant can be particularly favorable when the fiber composite material is conductive, for example by electrically conductive fibers such as carbon fibers. The layer of fiber composite material may then form a first electrode and on each scanning device a second electrode is provided, to which current from the first electrode in a direction perpendicular to the layer can flow through the molded part. Usually, a conductance or an electrical resistance of the molded part is determined, but in other embodiments, other, electrically scannable properties can be included, for example, capacitive or inductive properties of the molded part. One system includes the above-described molded article having a plurality of scanners, and a processing device configured to determine damage to the molded article based on the determined physical properties at the mounting locations of the scanners. If the scanning devices are wireless, it is preferred that the

Processing device handles the energy transfer to the scanning devices and / or the wireless communication with the scanning devices. The processing device can be provided separately from the molded part or fixedly attached to the molded part in order to be integrated with it. An interface of the processing device for providing a sampling or determination result is preferably carried out electrically.

In a particularly preferred embodiment, the processing means is arranged to determine damage to the molding when the determined physical property at a point in the surface is outside a predetermined range. For example, a range of about 5 to 500 Ω may be given for electrical resistance at the scanners. If the electrical resistance at a scanning device falls below the lower limit of the range or exceeds the upper limit, damage can be deduced. In this case, the specific physical property of each scanner can be individually compared with the area.

In a further embodiment, the processing means is arranged to determine a damage when the amount of a

Gradients of the particular physical property over the surface exceeds a predetermined threshold. In other words, damage may be determined when the change in the physical property in a direction along the surface exceeds a predetermined amount. For this purpose, either a curvature or a slope of a curve can be considered, which is defined by support points, which is defined by certain physical properties at the individual mounting locations. In another embodiment, it may also be checked whether the magnitude of the gradient is outside a predetermined range. A method of determining damage to a molded article, wherein the molded article comprises a layer of fiber composite extending along a surface, comprises steps of determining a physical property of the molded article by means of a scanner, the scanner being fixedly attached to the molded article at a predetermined mounting location , and determining the damage based on the determined physical property. The method can be carried out in particular by means of the processing device described above with regard to the system. Features that are described with respect to the method, the system and the molding, can be applied to the

Items of the other categories.

The physical property may be determined first and second times, the damage being determined based on a change in the particular physical property between the determinations. One or more scanners may be mounted anywhere on the molding and the first scan may be a calibration to which the following measurements may be compared. If a change in the physical parameter sensed at a location exceeds a predetermined level, damage may be expected.

In particular, a gradual progressive damage, for example, due to a spread of water in the molding, can be detected so sure. In another embodiment, damage may also be determined if one of the particular parameters changes faster than provided by another predetermined amount. Further, the damage may be determined if the relative change (or rate of change) of the particular parameter at one location differs from the relative change (or rate of change) of the particular parameter elsewhere by more than a predetermined amount.

It is generally preferred that measurements of different scanners do not affect each other. For this purpose, the scanning devices may be provided at predetermined minimum distances on the molded part or measurements of close to each other

Scanning devices can be performed with a time delay. Preferably, a plurality of scanners are distributed in the planar direction on the layer, wherein the processing means is adapted to interpolate the physical property between locations of the scanning and to determine damage of the molded part based on a course of the interpolated property in the planar direction.

The interpolation may be along a curve of the surface or along a portion of the surface. Due to the specific physical properties at the mounting locations of the scanning devices, interpolation points are specified between which interpolation takes place. The interpolation can take place in any desired manner, for example by means of a Bezier curve, a spline or a polynomial. As a result, an improvement can be detected which concerns only a small area of the layer, for example a puncture or a microcrack.

The method can be present in particular in the form of a computer program product with program code means, wherein the computer program product can run at least partially on the processing device described above. The processing device preferably comprises a programmable microcomputer, microcontroller or an FPGA.

The invention will now be described in more detail with reference to the attached figures, in which:

1 shows a molded part with a fiber composite material.

2 shows a molded part with a damage;

3 shows an interpolation of a physical property of a

Molding; and

4 is a flowchart of a method for determining a

Damage to a molded part represents. FIG. 1 shows a system 100 comprising a molding 105 and a processing device 110. The molding 105 comprises at least one layer 15 of a fiber composite material and an optional support structure 120. The layer 15 generally comprises fibers which are embedded in a matrix. In particular, the layer 1 15 a glass fiber reinforced plastic

(GRP) or a carbon fiber reinforced plastic (CFRP) include, but other fibers can be used, such as aramid or textile fibers. It can also be used a mixed construction with different fibers. It is also possible for a plurality of layers 11, which differ, for example, with respect to their fiber directions, to be encompassed by the molded part 105, wherein the layers are particularly preferably connected to one another in a flat manner. The support structure 120 may be connected to the surface 1 15 flat or lie between two layers 15 1; This structure is also called sandwich construction. The support structure 120 is preferably formed as a foam core, for example based on a hard foam, which may comprise about polyethylene, polystyrene or polyurethane. The processing device 110 may be constructed integrally with the molded part 105, for example, by the processing device 1 10 being fixedly attached to the layer 1 15 or enclosed in a cavity bounded on at least one side by the layer 15. In one embodiment, the

Processing device 1 10 arranged in a recess of the support structure 120.

The layer 1 15 extends along a surface 125, the dimensions of which are indicated by way of example in FIG. 1 as x and y. In this case, the surface 125 need not be flat, but can be arbitrarily shaped and in particular curved. There are also hollow body possible, for example, a hollow cylinder or a hollow sphere. In the layer 1 15 at least one scanning device 130 is firmly attached. The

Scanning device 130 can be attached to layer 1 15, in particular after the molding 105 has been produced, for example by means of lamination. If the molded part 105 comprises an inner side and an outer side, then it is preferable to provide the scanning device 130 on the inner side. The scanning device 130 is set up to determine a physical property of the molded part 105 locally, ie at the respective mounting location of the scanning device 130. The For example, physical property may include an electrical parameter, thermal conductivity, heat capacity, or reflective properties related to excitation of the scanner 130. The excitation may in particular comprise a mechanical oscillation, which may be particularly in the ultrasonic range. The

Scanning device 130 may for this purpose comprise a first sound transducer, which is adapted to initiate structure-borne noise on the molded part 105 as a transmitter, and a second sound transducer to scan a reflected sound wave as a receiver. Both transducers can each be designed as a piezo transducer. In one embodiment, a single piezo-transducer is successively called

Transmitter and used as a receiver. In other embodiments, transmitters and / or receivers may also be used for another test signal, such as an electrical signal or an electromagnetic wave. The wave can be at any frequency, so it can range from heat radiation, visible light and radio waves, to radar or X-rays.

It is particularly preferred that each scanning device 130 determines the respective physical parameter locally, ie at its respective mounting location. A mutual influence of different

Scanning 130 should be avoided as possible. For this purpose, in particular the physical parameter in a direction perpendicular to the surface 125, ie in the thickness direction can be determined. In the case of a curved surface 125, as in the exemplary embodiment of the molded part 105 shown in FIG. 1, the absolute direction is perpendicular to the surface 125 of the respective one

Location dependent. If the molded part 105 has different thicknesses in the region of different scanning devices 130, this can not affect a measurement because of the independence of the parameters sampled by the scanning devices 130.

The processing device 110 is configured to determine damage to the molding 105 based on certain physical parameters of the scanning device 130. For this purpose, the processing device 1 10 is connected at least in terms of data technology and at least temporarily to each of the scanning devices 130. The data connection can be wireless or wired. Usually, the Scanners 130 are also powered. This energy can be provided by the processing device 1 10, wherein alternatively a wired or wireless transmission is possible. A result provided by the processing device 110 regarding damage to the molding 105 may be provided to the outside by means of an interface 135.

Exemplary values for the physical parameter at the individual scanning devices 130 are shown in FIG. 1 as support points 140. The support points 140 are distributed to the mounting locations of the respectively associated scanning devices 130 along the surface 125. Graphically, the support points 140 are each shown in a direction perpendicular to the surface 125. Thus, the support points 140 define a further surface 145 which essentially follows the surface 125 in its extent and whose distance to the surface 125 at each of its points depends on the size of the physical parameter determined in the respective region. In order to determine the further area 145, an interpolation can be carried out between the attachment locations of the scanning devices 130, as will be described in more detail below with reference to FIG. For the consideration of the distance of the further surface 145 from the surface 125 or the layer 1 15, the shape, in particular the curvature of the surface 125 is not significant. The molded part 105 can therefore be shaped as desired.

Damage to the molded part 105 can be determined if a distance between the further surface 145 and the surface 125 or the layer 1 15 exceeds or falls below a predetermined distance.

FIG. 2 shows a molded part 105 with a damage 205. The damage 205 may include a crack, a hole, a pinch or a delamination. The illustrated damage 205 includes a number of very small ones

Cracks forming a shape similar to a spider web. The delamination usually comprises a detachment of the layer 1 15 from a region adjacent to the surface, such as the support structure 120 or another layer 1 15. The damage 205 can be detected, because at locations of scanning devices 130 in the region of the damage 205, the determined physical parameter is significantly smaller than in a remaining area. While most samplers 130 return similar values for the particular physical parameter, the values of the samplers 130 in the region of the damage 205 deviate significantly therefrom. For example, if an electrical resistance of the molded part 105 is determined in a direction perpendicular to the surface 125, the determined value in a damage-free region may be about 10, while in the region of damage 205 it may be about 100,000. In a simple embodiment, the damage 205 may be recognized by the fact that the particular physical parameter is outside a predetermined range. In another embodiment, the damage 205 may be detected when the parameter exceeds or falls below a predetermined threshold.

FIG. 3 shows an exemplary interpolation of a physical property p of the molded part 105 of FIGS. 1 or 2. In a purely exemplary manner, an extension of the layer 15 along the surface 125 is shown in the horizontal direction, purely in the x-direction, and in FIG vertical direction is the value of a physical parameter that reflects the physical property. In an upper illustration, four exemplary support points 140 are shown at attachment locations x1 to x4. Through the support points 140 runs a first curve, which was interpolated between the mounting locations x1 to x4. That is, values of the physical parameter p between the mounting locations x1 to x4 were calculated on the basis of the existing fulcrums 140. The first curve 305 forms a circular arc in the present example. Although none of the pads 140 are outside of a predetermined region 310 indicative of a damage-free portion of the molding 105, the first curve 305 exceeds the region 310 between the mounting locations x2 and x3. If it is used as the criterion for determining the damage 205 that the (interpolated) first curve 305 is outside the range 310, then a small or weak damage 205 can also be detected in an improved manner.

In the lower area of FIG. 3, a second curve 315 is shown, which reflects a curvature of the first curve 305. This curvature can be understood as the amount of a gradient of the first curve 305. In another

Embodiment, the damage 205 may be detected when the second Curve 315 is outside of another predetermined range 320. As a result, in particular, an abrupt transition or a point of discontinuity of the further surface 145 can be used as an indication of a damage 205. FIG. 4 shows a flow diagram of a method 400 for determining a

Damage 205 of a molded part 105. The method 400 is set up in particular for running on the processing device 110. By means of the method 400, it can be determined whether the molded part 105 has a damage 205 or not.

In a step 405, physical parameters p of the molded part 105 are preferably determined at a plurality of mounting locations of the layer 1 15 of the molded part 105. Preferably, a scanning device 130 is permanently assigned to each mounting location, which is fixedly attached to the layer 1 15 at the respective mounting location. The scanners 130 may be controlled simultaneously or sequentially to determine the physical parameter p. In a step 410, each of the determined values of the physical parameter p may be compared to a lower threshold and / or an upper threshold. If the parameter p exceeds the threshold value, there is damage 205 at the assigned mounting location.

Optionally, in a step 415 interpolation points 140 of individual scanning devices 130 can be interpolated, as explained in greater detail above with reference to FIG. The interpolation may be along a curve 305 or a

Surface 145. In this case, the entire molded part 105 or only a portion thereof may be covered. In a subsequent step 420, a comparison of the values of the curve 305 or the surface 145 with a lower threshold and / or an upper threshold may be performed. Is a portion of the curve 305 or the surface 145 beyond one of

Thresholds, so 205 can be closed on a damage.

Further optionally, in step 425, the amount of a gradient of the curve 305 or the surface 145 may be determined. This amount may be compared to a lower and / or upper threshold in step 430 become. If the magnitude of the gradient is beyond one of the thresholds, the damage 205 can be deduced.

The method 400 may be event driven or scheduled. In one embodiment, the method 400 is periodically executed to realize constant monitoring of the molding 105 for freedom from damage.

reference numeral

100 system

105 molded part

1 10 processing device

1 15 layer (fiber composite material)

120 carrier structure

125 area

130 scanning device

135 interface

140 support point

145 more area

205 damage

305 first turn

310 area

315 second turn

320 area

400 procedures

405 sampling

410 single comparison with area

415 Interpolate curve or surface

420 Comparison with area

Determine 425 gradient

Comparison of the amount of the gradient with area or

threshold

Claims

claims

1 . Molded part (105), wherein the molded part (105) comprises:

a layer (1 15) of fiber composite material, wherein the layer (1 15) along a surface (125) extends; and

a scanner (130) fixedly mounted on the molding (105) and adapted to determine a physical property (p) of the molding (105) at an attachment location (x) of the scanner (130). 2. molding (105) according to claim 1, wherein a plurality of scanning devices

(130) distributed in the planar direction on the layer (1 15) is mounted.

3. molding (105) according to claim 1 or 2, wherein the physical property (p) along a direction perpendicular to the layer (1 15) is determined.

4. molding (105) according to any one of the preceding claims, wherein the

physical property is dependent on damage of the molded part. 5. molded part (105) according to claim 4, wherein the layer (1 15) flat with another layer (120) is connected and the damage (205) a detachment of a portion of the layer (1 15) of another layer (120). includes. 6. molding (105) according to claim 4, wherein the support structure (120) is connected flat with two layers (1 15), which lie on different sides of the support structure (120).

7. molding (105) according to any one of the preceding claims, wherein the

Scanning device (130) comprises a transmitter for a wave propagating in the molded part (105) and a receiver for a reflection of the wave.

A molding (105) according to any one of the preceding claims, wherein the scanning means (130) comprises a circuit comprising a portion of the Moldings (105) in a direction perpendicular to the layer (1 15) flows through.

A system (100) comprising a molding (105) according to any one of claims 2 to 8 and processing means (110) adapted to damage (205) the molding (105) based on the determined physical properties (p) at sites (x) of

To determine scanning devices (130).

The system (100) of claim 9, wherein the processing means (110) is arranged to determine damage (205) if the determined physical property (p) at a point in the surface (125) is outside a predetermined range (310) lies.

1 1. The system (100) of claim 9 or 10, wherein the processing means (110) is arranged to determine damage (205) when the magnitude of a gradient (315) of the particular physical

Property (p) over the area (145) exceeds a predetermined threshold. 12. A method (400) for determining a damage (205) of a molded part (105), wherein the molded part (105) comprises a layer (1 15)

Fiber composite material extending along a surface (125), and the method (400) comprises the steps of:

Determining (405) a physical property of the molding (105) by means of a scanner (130), the scanner (130) being fixedly attached to the molding (105) at a predetermined attachment location (x); and

Determining (410) the damage based on the determined physical property.

13. The method of claim 12, wherein the method (400) comprises the steps of:

Determining (405) a physical property of the molding (105) at predetermined attachment locations (x) distributed in the planar direction on the molding (105); Determining (425) a gradient (315) of the determined physical property (p) across the surface (145);

Comparing (430) an amount of the gradient with a predetermined threshold; and

Determining (410) damage if the magnitude of the gradient exceeds the threshold.

14. The method (400) according to claim 12 or 13, wherein the physical

Property (405) is determined a first and a second times, and the damage is determined (410) based on a change in the particular physical property between the determinations.

The method (400) of any one of claims 12 to 14, wherein a plurality of scanners (130) are distributed in the planar direction on the layer (1 15); where the physical property (p) is between

Mounting locations (x) of the scanning devices (130) interpolated and damage (205) of the molding (105) on the basis of a course (145, 305) of the interpolated property (p) in the surface direction is determined. 16 computer program product with program code means for performing a method (400) according to any one of claims 12 to 15, wherein the computer program product on a processing device (1 10) is executed or stored on a computer-readable medium.