Method and system for determining tension and / or well failure

Abstract

Methods and systems are provided for analyzing a stamped part having a final shape for a vehicle. A method includes: receiving data of a stamped part; generating a computer simulation based on the data; generating a computer simulation in response to the processor to determine a wrinkle index (WI) of the stamped part; determining whether the analyzed element is located at the trim edge of the stamped part; determining a tensile index (SI) of the trimmed edge portion when the analyzed element is located at the trimmed edge of the stamped part, or determining SI of the planar stress portion in response to a computer simulation generated by the processor when the analyzed element is not located at the trimmed edge of the stamped part; comparing the SI with an SI threshold value and / or comparing the SI with the WI; and generating, using a processor, a Unified Failure Index (UFI).

Description

Technical Field

[0001] The present disclosure relates generally to the development of stamping dies and, more particularly, to combining tensile-based fracture failure and geometry-based wrinkle failure into one failure test. Background Art

[0002] Automobile manufacturers are continually researching improvements to the manufacturing processes for motor vehicle components. For example, stamping is a manufacturing process used to produce sheet metal components. During the stamping process, a die and a blank holder cooperate to hold a piece of sheet metal, or so-called blank, in a fixed position. The die includes a die cavity, and a punch draws the sheet metal into the die cavity to form a workpiece having a desired shape associated with the die cavity. The blank holder includes a bead for engaging the sheet metal and controlling the amount of sheet metal that flows into the die cavity. Insufficient sheet metal flow can result in tensile failures, such as fractures, while excessive metal flow can result in wrinkling.

[0003] Workpieces such as stamped sheets may exhibit a variety of failures. For example, a tensile-based fracture failure may be located within the sheet, a tensile-based fracture failure may be located at the trimmed edge of the sheet, and a geometry-based wrinkle failure may be located on the sheet. In industrial practice, technicians manually perform multiple methods with independent related criteria to identify failures in different parts of the workpiece. This process introduces complexity and uncertainty to failure detection, which in turn reduces the efficiency of stamping die development.

[0004] Therefore, while existing methods and systems for developing stamping dies achieve their intended purposes, a new and improved method and system for developing stamping dies that addresses these problems is needed. Summary of the invention

[0005] A method for analyzing a stamped part having a final shape for a motor vehicle is provided and includes: receiving data of the stamped part using a processor; generating a computer simulation based on the data using the processor; determining a wrinkle index (WI) of the stamped part using the processor in response to the processor generating the computer simulation; determining whether the analyzed element is located at the trimmed edge of the stamped part using the processor in response to the processor generating the computer simulation when the analyzed element is located at the trimmed edge of the stamped part, or determining the SI of the plane stress portion using the processor in response to the processor generating the computer simulation when the analyzed element is not located at the trimmed edge of the stamped part; comparing the SI with an SI threshold and / or comparing the SI with the WI; and generating a uniform failure index (UFI) equal to the SI using the processor in response to the processor determining that the SI is greater than the SI threshold, generating a UFI equal to the SI in response to the processor determining that the SI index is not greater than the SI threshold and greater than the absolute value of the WI, and generating a UFI equal to the WI in response to the processor determining that the SI is not greater than the SI threshold and not greater than the absolute value of the WI.

[0006] In some embodiments, the method further comprises: generating, using the processor, a tensile failure signal in response to the processor determining that the SI is greater than an SI threshold; and indicating, using the display device, that the stamped part has a fracture in response to the display device receiving the tensile failure signal.

[0007] In some embodiments, the method further includes: generating a wrinkle failure signal using the processor in response to the processor determining that the WI is less than the WI threshold; and indicating using the display device that the stamped part has wrinkles in response to the display device receiving the wrinkle failure signal.

[0008] In some embodiments, the method further includes: using a processor to generate a tensile failure signal in response to the processor determining that the SI is greater than a tensile index threshold; otherwise, using a processor to generate a wrinkle failure signal in response to the processor determining that the absolute WI value is less than the WI threshold; and using a display device to indicate that the stamped part has a fracture in response to the display device receiving the tensile failure signal, and indicating that the stamped part has a wrinkle in response to the display device receiving the wrinkle failure signal.

[0009] In some embodiments of the method, the SI threshold is 1 and the WI threshold is -1.

[0010] In some embodiments of the method, determining, using a processor, whether the component being analyzed is located at a trimmed edge of a stamped part is performed using the following evaluations:

[0011] Assuming a linear strain path at each operation, which is correct for most stamping operations, for each element the ratio between the incremental small strain and the large strain at each time step i of operation p is calculated according to formula (3.1):

[0012]

[0013] in, and is the incremental small strain and large strain calculated according to formula (3.2):

[0014]

[0015] Among them, the normal anisotropy parameter is used Under uniaxial tension, the critical strain ratio ρ u Approx. And according to formula (3.3), the analyzed element is determined to be located at the trimmed edge of the stamped part:

[0016] 0.9ρ u ≤ρ p (i)≤1.1ρ u (3.3).

[0017] This method can be used together with other methods to determine the trimmed edge, for example to check whether the component has a free edge.

[0018] In some embodiments of the method, determining the SI of the trimmed edge portion using the processor in response to the processor generating the computer simulation includes determining a maximum SI based on a plurality of stretch indices.

[0019] In some embodiments of the method, determining the SI of the plane stress portion using the processor in response to the processor generating a computer simulation includes determining the SI according to formula (1.1):

[0020]

[0021] In some embodiments of the method, determining the SI of the trimmed edge portion using the processor in response to the processor generating the computer simulation includes determining the SI according to formula (1.2):

[0022]

[0023] In some embodiments of the method, determining the SI of the plane stress portion using the processor in response to the processor generating a computer simulation includes determining a maximum SI based on a plurality of stretch indices.

[0024] In some embodiments of the method, determining the WI of the stamped part using the processor in response to the processor generating the computer simulation includes determining the WI according to formula (1.3):

[0025]

[0026] In some embodiments, the method further comprises displaying a visual indication of the stretch index and the wrinkle index associated with the computer simulation.

[0027] A system for analyzing a stamped part having a final shape for a motor vehicle is provided, and includes a processor configured to: receive data of the stamped part; generate a computer simulation based on the data; determine a WI of the stamped part in response to the processor generating the computer simulation; determine whether the analyzed element is located at the trimmed edge of the stamped part; when the analyzed element is located at the trimmed edge of the stamped part, determine the SI of the trimmed edge portion; when the analyzed element is not located at the trimmed edge of the stamped part, determine the SI of the plane stress portion; compare the SI with an SI threshold and / or compare the SI with the WI; and generate a unified failure index (UFI) equal to the SI in response to determining that the SI is greater than an index threshold, generate a UFI equal to the SI in response to determining that the SI is not greater than a tensile index threshold and is greater than the absolute value of the WI, and generate a UFI equal to the WI in response to determining that the SI is not greater than the SI threshold and is not greater than the absolute value of the WI; and a display device electrically coupled to the processor and configured to visually indicate a tensile index and a wrinkle index associated with the computer simulation.

[0028] In some embodiments of the system, the processor is configured to generate a tensile failure signal in response to determining that the SI is greater than the SI threshold; and the display device is configured to indicate that the stamped part has a fracture in response to the display device receiving the tensile failure signal.

[0029] In some embodiments of the system, the processor is configured to generate a wrinkle failure signal in response to the processor determining that WI is less than a WI threshold; and the display device is configured to indicate that the stamped part has wrinkles in response to the display device receiving the wrinkle failure signal.

[0030] In some embodiments of the system, the processor is configured to generate a tensile failure signal in response to determining that SI is greater than an SI threshold; the processor is configured to generate a wrinkle failure signal in response to the processor determining that WI is less than a WI threshold; and the display device is configured to indicate that the stamped part has a fracture in response to the display device receiving the tensile failure signal; and the display device is configured to indicate that the stamped part has a wrinkle in response to the display device receiving the wrinkle failure signal.

[0031] A system for producing a die is provided, the die being configured to form a sheet metal blank into a workpiece for a stamped part, the stamped part having a final shape for a motor vehicle, wherein the workpiece has a bead-affected portion, a trimmed edge portion, and a plane stress portion, the system comprising: a processor, the processor being configured to: receive data of at least one of a die design, a part design, and a stamping process plan associated with the workpiece; generate a computer simulation based on the data; in response to the processor generating the computer simulation, determine an SI of an associated one of the bead-affected portion, the trimmed edge portion, and the plane stress portion of the workpiece; and The SI of each of the surface stress portions is compared to an SI threshold; and in response to the processor determining that the SI of at least one of the bead-affected portion, the trimmed edge portion, and the plane stress portion is greater than the tensile index threshold, a tensile failure signal is generated; in response to the processor generating a computer simulation to determine the WI of the workpiece; comparing the WI to the WI threshold; and in response to the processor determining that the WI is less than the wrinkle index threshold, a wrinkle is generated. Failure signal, that is, when (WI≤-1), wrinkles are reported; receiving data of at least one of a changed die design, a changed part design, and a changed stamping process plan associated with the workpiece; based on the changed data a computer simulation of the change generated by the processor; in response to the processor generating the computer simulation of the change, determining the changed SI of an associated one of the bead-affected portion, the trimmed edge portion, and the plane stress portion of the workpiece; and in response to the processor determining that one of the SI of each of the bead-affected portion, the trimmed edge portion, and the plane stress portion and the changed SI is less than an SI threshold, generating a stretch acceptance signal; in response to the processor generating the computer simulation of the change, determining the changed WI of the workpiece; and in response to the processor determining that the changed WI is within a wrinkle index threshold, i.e., when the changed WI>-1, generating a wrinkle acceptance signal; and a display device, displaying the device The backup device is electrically coupled to the processor and is configured to: in response to the display device receiving a stretch failure signal and / or a wrinkle failure signal, indicate that the workpiece has a fracture and / or wrinkle, and prompt a user to input changed data into the processor; in response to the display device receiving a stretch acceptance signal and / or a wrinkle acceptance signal, indicate that the workpiece does not have a fracture and / or wrinkle, so that the processor sends the stretch acceptance signal and / or the wrinkle acceptance signal to a mold manufacturing device, the mold manufacturing device is used to transform the tool material into a mold associated with one of the SI and the changed SI that is less than a stretch index threshold and one of the WI and the changed WI that is greater than a WI threshold.

[0032] In some embodiments of the system, the processor is configured to receive data associated with a part design, wherein the data includes at least one of a geometry of the stamped part and at least one material property of a sheet of metal forming the stamped part.

[0033] In some embodiments of the system, the processor is configured to generate a bead-affected tensile failure signal in response to the processor determining that the SI of the bead-affected portion is greater than a tensile index threshold, and the display device indicates that a fracture is set in the bead-affected portion in response to the display device receiving the bead-affected tensile failure signal from the processor.

[0034] In some embodiments of the system, the processor is configured to generate a trimmed edge stretch failure signal in response to the processor determining that the SI of the trimmed edge portion is greater than a stretch index threshold, and the display device indicates that a break is set in the trimmed edge portion in response to the display device receiving the trimmed edge stretch failure signal from the processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present disclosure will hereinafter be described in conjunction with the following drawings, wherein like numerals represent like elements, and wherein:

[0036] Figure 1 is a schematic diagram of one example of a system for producing a die for a stamping press that forms sheet metal blanks into stamped parts for motor vehicles.

[0037] Figure 2 yes Figure 1 An enlarged view of the punch shown in FIG.

[0038] Figure 3 is a schematic diagram showing wrinkle risk calculation.

[0039] Figure 4 Is used for operation Figure 1 A flowchart of an example of a method of a system.

[0040] Figure 5 Is used for operation Figure 1 A flowchart of an example of a method of a system.

[0041] Figure 6 is a flow chart of an example of a method for optimizing a stamping process using UFI. DETAILED DESCRIPTION

[0042] The following detailed description is merely exemplary in nature and is not intended to limit application and use. In addition, there is no intention to be bound by any express or implied theory presented in the foregoing background technology, the invention content, or the following detailed description. As used herein, the term module refers to any hardware, software, firmware, electronic control unit or component, processing logic and / or processor device, alone or in any combination, including but not limited to: application-specific integrated circuits (ASICs), electronic circuits, processors (shared, dedicated or groups) and memories that execute one or more software or firmware programs, combinational logic circuits, and / or other suitable components that provide the described functions.

[0043] Embodiments of the present disclosure may be described herein in terms of functional and / or logical block components and various processing steps. It should be understood that such block components may be implemented by any number of hardware, software, and / or firmware components configured to perform specified functions. For example, embodiments of the present disclosure may employ various integrated circuit components, such as memory elements, digital signal processing elements, logic elements, lookup tables, etc., which may perform various functions under the control of one or more microprocessors or other control devices. In addition, those skilled in the art will appreciate that embodiments of the present disclosure may be practiced in conjunction with any number of autonomous driving systems, including cruise control systems, automatic driver assistance systems, and autonomous driving systems, and that the vehicle system described herein is merely an example embodiment of the present disclosure.

[0044] For the sake of brevity, conventional techniques related to signal processing, data transmission, signaling, control, and other functional aspects of the system (and the individual operating components of the system) may not be described in detail herein. In addition, the connecting lines shown in the various figures included herein are intended to represent example functional relationships and / or physical connections between various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in the embodiments of the present disclosure.

[0045] An exemplary system and method for reporting tensile failure in stamping die development combines three standards and processes for detecting three different types of tensile failure into one tensile index (SI) representation. Examples of tensile failures include trim edge fractures, local necking and subsequent fractures in the bead-affected zone, and local necking and subsequent fractures under plane stress conditions. The system and method display the tensile failure risk in a unified SI representation, for example, by a one-click operation of a technician. The technician can use the detected tensile failure risk for practical applications, i.e., changing the design of the die, part, stamping process plan, or any combination thereof, and producing the associated die that converts the sheet metal blank into a stamping part with a reduced risk of tensile failure. Non-limiting examples of changing the design may include adjusting the bead shape or the blank shape and changing the shape features on the stamping part, thereby allowing the corresponding shape on the stamping die to change. It is conceivable that the method and system may include any number of other changes to the design and the associated manufacturing die and stamping parts.

[0046] The processor generates a computer simulation for practical application, i.e., identifies and corrects design problems of molds, parts, and stamping process plans before finalizing the design, and uses a mold machining device to build a mold associated with the finalized design. To this end, this article can be based on functional and / or logical block components, and with reference to symbolic representations of operations, processing tasks, and functions that can be performed by various computing components or devices to describe techniques and skills. Such operations, tasks, and functions are sometimes referred to as computer execution, computerization, software implementation, or computer implementation. In practice, one or more processor devices can perform the described operations, tasks, and functions by manipulating electrical signals representing data bits at memory locations in system memory and other processing of signals. The memory location that holds the data bit is a physical location with specific electrical, magnetic, optical, or organic properties corresponding to the data bit. It should be understood that the various block components shown in the figure can be implemented by any number of hardware, software, and / or firmware components configured to perform the specified functions.

[0047] This specification relates to examples of methods and systems that employ steps and activities performed by modules, including computers that employ discrete rules and calculations that are integrated into practical applications, such as the manufacture of physical items. In this example, the method and system use one or more modules to transform tool materials into dies that produce stamping parts that meet complex standards. Practical applications of the present disclosure include elements that implement or use computers and / or mental activities in conjunction with specific and integral machines and manufactured products. The specific machines employed and the beneficial results achieved are tangible and physical. The disclosed activities are practical and solve technical challenges. More specifically, in this example, the method and system use sheet metal forming simulations to apply index thresholds for multiple standards and related parts for stamping parts in order to provide robust analysis of die design, reduce human errors, and simplify stamping operations. In addition, for example, the method and system can accurately produce higher quality dies and related stamping parts, thereby requiring fewer hardware modifications.

[0048] The module can be implemented in whole or in part as a hardware circuit including discrete components. The module can also be implemented in a programmable hardware device, a programmable logic device, etc. The module can also be implemented in software for execution by various types of processors. The identified executable code module can, for example, include one or more physical or logical modules of computer instructions, which can, for example, be organized as an object, a program, or a function. However, the executable program of the identified module does not need to be physically located together, but can include different instructions stored in different locations, which, when logically combined together, include the module and realize the purpose of the module. In fact, the module of the executable code can be a single instruction or multiple instructions, and can even be distributed on several different code segments, between different programs, and between several memory devices. Similarly, the operable data can be embodied in any suitable form and organized in any suitable type of data structure. The operable data can be collected as a single data set, or can be distributed in different locations, including different storage devices, and can exist only as electronic signals on a system or network at least in part.

[0049] Reference now Figure 1 and Figure 2 , a system 100 is provided for converting a tool material 102 into a die 104 of a punch press 106, which in turn is configured to punch a sheet metal blank 108 ( Figure 2 ) is formed into a stamped part 110 of a motor vehicle. Figure 2As best shown, the die 104 includes an upper die half 112, a binder 115, and a lower die half 114, all fixed in the punch press 106. The die halves 112, 114 have corresponding complementary die surfaces 116, 118 facing each other. The upper die half 112 has a male bead 117a, and the binder 115 has a groove or recess 117b associated with the male bead 117a. The upper die half 112 is configured to move downward and clamp the metal sheet blank 108 with the binder 115. The upper die half 112 is configured to move further downward with the binder 115, which is supported by the buffer pins, to stretch the metal sheet blank 108 flowing over the bead and into the die cavity between the die surfaces 116, 118. The die surfaces 116, 118 are configured to form the metal sheet blank 108 and change its shape into a workpiece that reflects the contours of the die surfaces 116 and 118. In another example (not shown), the die may include a lower die half having a die cavity and a punch for pulling the sheet metal blank into the die cavity. The die 104 may be one of a series of dies through which the sheet metal blank is gradually processed to change the sheet metal blank into the shape of the finished product. Before building the die, the design of the die, stamped parts, and stamping process plan will be evaluated using simulation tools and 3D mathematical data of the finished stamped parts to be produced. This provides the ability to make any necessary corrections in a computer simulation compared to a physical die, thereby saving a significant amount of time and expense.

[0050] In this example, the system 100 includes one or more computing devices 122 for generating simulations to identify and correct problems before finalizing the mold design and actuating the mold manufacturing equipment 120 to build the mold. The computing device 122 includes at least one processor 124, a processor-readable medium 126, and some form of input and output hardware. The program or code segment can be stored in the processor-readable medium 126, or transmitted on a transmission medium or communication path by a computer data signal embodied in a carrier. "Processor-readable medium", "computer-readable medium" or "machine-readable medium" can include any temporary or non-temporary medium that can store or transfer information. Examples of processor-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, or any combination thereof. Computer data signals can include any signal that can be propagated on a transmission medium such as an electronic network channel, optical fiber, air, electromagnetic path, or RF link. The code segment can be downloaded via a computer network such as the Internet, an intranet, a LAN, etc.

[0051] The computing device 122 can be an independent computer system, a portable computing device, or a personal computing device (e.g., a tablet computer, a laptop computer, a personal digital assistant (PDA), a smart phone), etc. For the purpose of the present disclosure, the computing device 122 is capable of storing, maintaining, and executing programs, code segments, or other instructions configured to use a mesh data file to evaluate various aspects of a stamping operation (including a die). However, it is further contemplated that the processor can store other software tools that generate simulations without using a mesh data model. In addition, the computing device 122 includes a display device 128 electrically coupled to the processor 124 for displaying visualizations 130, such as visualizations of application pages, part surfaces, and die surfaces. The visualization of the part surface can include an indication or description of a part fracture.

[0052] In the exemplary embodiment, the mold manufacturing equipment 120 is configured to transform the tool material into the mold 104. In this example, the mold manufacturing equipment 120 is a computer numerical control machine 132, which is configured to perform a material removal operation in response to the computer numerical control machine receiving a stretch acceptance signal from a processor. However, it is contemplated that the mold manufacturing equipment can be other metal removal machines used to build the mold 104, which in turn can be used in the stamping machine 106 for producing the stamped part 110.

[0053] The processor 124 is configured to receive data of at least one of a die design, a part design, and a stamping process plan associated with the workpiece. The data associated with the part design may include the geometry of the stamped part and one or more material properties of the sheet metal forming the stamped part. It is contemplated that the data may include other suitable parameters of the final stamped part to be produced.

[0054] The processor 124 is also configured to generate a computer simulation of the die 104 based on the data. In response to the processor 124 receiving the part data, the processor 124 can generate the computer simulation using a software application such as a computer-aided design (CAD) stored on the processor-readable medium 126. The simulation of the die generates an associated simulated stamped part having a bead-affected portion, a trimmed edge portion, and a plane stress portion.

[0055] The processor 124 is configured to handle fractures and wrinkles, which are two major failures in sheet metal forming. In the forming simulation analysis, the fracture risk can be analyzed by: (1) checking the maximum failure through the forming limit diagram; (2) checking the thinning of internal planar elements; and (3) checking the large strain of edge fracture. Then, wrinkle defects are detected through geometry-based evaluation. Herein, a unified failure index tool is proposed to report both fractures and wrinkles in a single view. A binary decision algorithm is implemented as a function in a software application (such as AutoForm). Therefore, the above four-step operation is automatically implemented in one step. As a result, at least 75% efficiency improvement can be achieved.

[0056] As described herein, the unified failure index (UFI) represents the wrinkle index (WI) in the negative domain and the tensile failure index (SI) in the positive domain as follows:

[0057]

[0058] where, for each element, at operation p and time step (i), It's a big strain. It's a small strain. In response to small strain The maximum strain limit along the linear strain path or nonlinear strain path, th p (i) is thinning, As a small strain The thinning limit of the function .

[0059] Figure 3 The wrinkle risk calculation for the sheet 110 is shown. The wrinkle index (WI) is a function w representing the wrinkle risk and a threshold w above which wrinkles are reported. c The wrinkle index (WI) can be determined by correlation with the physical metal sheet panel in forming and simulation. Figure 3 As shown, W is calculated by formula (2.1):

[0060]

[0061] Where t is the sheet thickness, R s is the radius of the sheet being formed, and R T is the radius of the tool surface to be contacted. Figure 3 The radius R of the tool surface to be contacted T The radius R of the metal sheet being formed is indicated by reference numeral 1100. s Identified by reference numeral 1101 .

[0062] When the stretch index (SI) is less than 1 and the absolute value of the wrinkle index (WI) is greater than SI, the UFI is reported as WI, otherwise, the UFI is equal to SI. Since WI is always negative and SI is always positive, when UFI is positive, the risk of breakage is reported, and the risk is proportional to the positive value; on the other hand, a negative UFI proportionally means the risk of wrinkling.

[0063] Additional embodiments are provided herein for determining SI at a trimmed edge or interior location of a metal sheet.

[0064] First, a strain ratio-based method is provided to detect whether the analyzed component is located on the trimmed edge of the metal sheet. Under the assumption of a linear strain path at each operation (which is correct for most stamping operations), for each component, the ratio between the incremental small strain and the large strain at each time step i of operation p is calculated in formula (3.1) as follows:

[0065]

[0066] in, and are the incremental small strain and large strain, as shown in formula (3.2):

[0067]

[0068] Using Normal Anisotropy Parameters Under uniaxial tension, the critical strain ratio ρ u Approx. The element of interest or the element under analysis is considered to be at the trimming edge when in equation (3.3):

[0069] 0.9ρ u ≤ρ p (i)≤1.1ρ u (3.3).

[0070] This method can be used together with other methods to determine the trimmed edge, for example to check whether the component has a free edge.

[0071] Additional embodiments provided herein can be adjusted for large strains under the influence of beads. Specifically, large strains at the bead influence area can be adjusted: for example, by the method given in U.S. Patent Publication 2022 / 0100923A1 or Keeler S., "The Enhanced FLC Effect", "A report for Auto / Steel Partnership, Keeler Technologies LLC, 2002", according to formula (4.1):

[0072]

[0073] in, and is the predicted large strain and thickness strain at time step (i) of operation p, which can be calculated according to formula (4.2) as:

[0074]

[0075] refer to Figure 4 , showing the operation Figure 1 The method 200 begins at block 302, where the processor 124 receives data associated with a die design, a part design, a stamping process plan, or any combination thereof. In one example, the processor 124 receives data associated with the part design, the data including at least one of a geometry of a stamped part and one or more material properties of a sheet of metal from which the stamped part is stamped.

[0076] At block 304, the processor 124 generates a computer simulation of the mold 104 in response to the processor 124 receiving the data. In another example, the processor 124 generates a changed computer simulation of the mold 104 in response to the processor 124 receiving the changed data.

[0077] At block 306, the processor 124 determines the wrinkle index (WI) of the panel. For example, the wrinkle index (WI) may be determined by formula (1.3):

[0078]

[0079] Where w is calculated by formula (2.1):

[0080]

[0081] where t is the sheet thickness,

[0082] R s is the radius of the metal sheet being formed,

[0083] R T is the radius of the tool plane to be contacted, and

[0084] w c is the threshold below which wrinkles are reported and can be determined by correlation with the physical metal sheet in forming and simulation.

[0085] The method 300 continues at block 310, where the processor 124 queries whether the inspected component is on the edge of the workpiece. For example, the processor 124 may determine whether the inspected component is on the edge of the workpiece using the following formula (3.1):

[0086]

[0087] in, and is the incremental minor strain and principal strain in formula (3.2), as shown below:

[0088]

[0089] Using Normal Anisotropy Parameters Under uniaxial tension, the critical strain ratio ρ u Approx. In formula (3.3), the element of interest is considered to be at the trimming edge:

[0090] 0.9ρ u ≤ρ p (i)≤1.1ρ u (3.3)

[0091] If the element is not on the edge, that is, the element is within the sheet panel, the method continues at box 312. At box 312, the processor 124 determines the stretch index (SI) of the element within the sheet panel. For example, the stretch index (SI) can be determined by formula (1.1):

[0092]

[0093] where, for each element, at operation p and time step (i), It's a big strain. It's a small strain. In response to small strain The maximum strain limit along the linear strain path or nonlinear strain path, th p (i) is thinning, As a small strain The thinning limit of the function .

[0094] If the element is on an edge, the method continues at block 314. At block 314, the processor 124 determines the stretch index (SI) of the element on the trimmed edge of the panel. For example, the stretch index (SI) may be determined by formula (1.2):

[0095]

[0096] As shown, after determining the stretch index (SI) at either block 312 or block 314 , the method continues at block 320 where the processor determines whether the stretch index is greater than or equal to one.

[0097] If the stretch index (SI) is not greater than or equal to 1, the method continues at box 330, where the processor determines whether the stretch index (SI) is greater than or equal to the absolute value of the wrinkle index (WI). If the stretch index (SI) is not greater than or equal to the absolute value of the wrinkle index (WI), the processor determines at box 332 that the unified failure index is equal to the wrinkle index (WI) determined at box 306.

[0098] Referring back to block 320 , if the processor determines that the tensile index (SI) is greater than or equal to 1, the method 300 continues at block 350 where the processor determines that the unified failure index is equal to the tensile index (SI) determined at blocks 312 or 314 .

[0099] Referring back to block 330 , if the processor determines that the stretch index (SI) is greater than or equal to the absolute value of the wrinkle index (WI), the method 300 continues at block 350 where the processor determines that the unified failure index is equal to the stretch index (SI) determined at blocks 312 or 314 .

[0100] Figure 5 Shows the operation Figure 1 The method 400 of the system 100 is similar to the method 300 from blocks 302 to 332. In the method 400, when the processor determines that the tensile index (SI) is greater than or equal to 1, then the method 400 continues at block 340, where the processor determines whether the component being inspected is in a bead-affected zone. If the component is not in a bead-affected zone, then the method 400 continues at block 350, where the processor determines that the unified failure index is equal to the tensile index (SI) determined at blocks 312 or 314.

[0101] When the element is in the bead influence zone, method 400 continues at block 342 where the processor adjusts for the large strain in the bead influence zone and updates SI according to equation (4.1):

[0102]

[0103] in, and is the predicted maximum strain and thickness strain at time step (i) of operation p, which can be calculated in equation (4.2) as:

[0104]

[0105] Among them, t i is the thickness of the current time step (i) of operation p, and t 0 is the original thickness.

[0106] After the processor adjusts the large strains, the method 400 continues at block 350 , where the uniform failure index (UFI) is equal to the tensile failure index (SI), as updated at action block 342 .

[0107] In certain embodiments, an algorithm is provided to implement UFI when evaluating simulation results. For each element at time step I of operation p, the algorithm loops through each element and performs the following steps:

[0108] (1) Start by checking whether the component is on the trimmed edge (block 310). If the component is on the trimmed edge, the SI is calculated by formula (1.2) (block 314). Otherwise, the SI is calculated by formula (1.1) (block 312).

[0109] (2) Check whether SI ≥ 1 (block 320), if yes, go to step 3, if no, go to step 6;

[0110] (3) Check whether the element being analyzed is in the bead influence zone (block 340), if yes, go to step 4, if no, go to step 5;

[0111] (4) Correct the bead effect and update SI by formula (4.1) (block 342), then go to step 5;

[0112] (5) UFI = SI (block 350)

[0113] (6) Check whether |WI|>SI, that is, whether the absolute value of WI is greater than SI (block 330). If so, go to step 7; otherwise, go to step 5;

[0114] (7) UFI=WI (block 332).

[0115] As described above, methods 300 and 400 each provide an algorithm for processing a unified failure index tool. In each of these methods, both the tensile failure index (SI) and the wrinkle index (WI) are considered in determining the unified failure index (UFI). These methods provide an effective process for evaluating failure. The traditional process using five steps can be simplified to an automated process with a one-click activation script.

[0116] Figure 6A method 500 for optimizing a stamping process using a unified failure index (UFI) is shown. As shown, the method 500 begins at box 502, where the processor 124 runs a forming simulation to form a simulated sheet. In addition, at box 504, the processor 124 reads the UFI, and then queries at box 506 whether the absolute value of the UFI at any location on the simulated sheet is greater than or equal to 1 (|UFI|≥1). If not, the method proceeds to box 508, where the method 500 indicates that the simulated sheet passes the formability analysis.

[0117] If it is determined at block 506 that the absolute value of the UFI at the location on the simulated sheet is greater than or equal to 1 (|UFI|≥1), the method 500 proceeds to block 510, which queries whether the UFI is greater than or equal to 1 (UFI≥1). If so, the method 500 proceeds to block 512, where the method addresses the risk of breakage. If not, the method 500 proceeds to block 516, which queries whether the UFI is less than or equal to -1 (UFI≤-1). If so, the method 500 proceeds to block 518, where the method addresses the risk of wrinkling.

[0118] After resolving the risk of fracture (at block 512 ) or the risk of wrinkling (at block 518 ), the method 500 continues at block 514 to update the process before repeating the method at block 502 .

[0119] Although at least one exemplary embodiment has been proposed in the foregoing detailed description, it should be understood that there are a large number of variations. It should also be understood that the exemplary embodiment or multiple exemplary embodiments are only examples and are not intended to limit the scope, applicability or configuration of the present disclosure in any way. On the contrary, the foregoing detailed description will provide a convenient roadmap for implementing the exemplary embodiment or multiple exemplary embodiments for those skilled in the art. It should be understood that various changes can be made to the functions and arrangements of the elements without departing from the scope of the present disclosure as set forth in the attached claims and their legal equivalents.

Claims

1. A method for analyzing a stamped part having a net shape for a motor vehicle, the method comprising: Using a processor to receive data of the stamped part; generating a computer simulation based on the data using the processor; determining a wrinkle index (WI) of the stamped part using the processor in response to the processor generating the computer simulation; determining, using the processor, whether the component being analyzed is located at a trimmed edge of the stamped part; determining a stretch index (SI) of a trimmed edge portion using the processor in response to the processor generating the computer simulation when the analyzed element is located at the trimmed edge of the stamped part, or determining the SI of a plane stress portion using the processor in response to the processor generating the computer simulation when the analyzed element is not located at the trimmed edge of the stamped part; comparing the SI with an SI threshold and / or comparing the SI with the WI; as well as Using the processor to generate a unified failure index (UFI) equal to the SI in response to the processor determining that the SI is greater than the SI threshold, to generate a UFI equal to the SI in response to the processor determining that the SI index is less than the SI threshold and greater than the absolute value of the WI, and to generate a UFI equal to the WI in response to the processor determining that the SI is less than the SI threshold and less than the absolute value of the WI.

2. The method according to claim 1, further comprising: generating, with the processor, a tensile failure signal in response to the processor determining that the SI is greater than the SI threshold; as well as A display device is used to indicate that the stamped part has a fracture in response to the display device receiving the tensile failure signal.

3. The method according to claim 1, further comprising: generating, using the processor, a wrinkle failure signal in response to the processor determining that the WI is less than a WI threshold; as well as A display device is used to indicate that the stamped part has a wrinkle in response to the display device receiving the wrinkle failure signal.

4. The method according to claim 1, further comprising: generating, with the processor, a tensile failure signal in response to the processor determining that the SI is greater than the SI threshold; generating, using the processor, a wrinkle failure signal in response to the processor determining that the WI is less than a WI threshold; as well as A display device is used to indicate that the stamped part has a fracture in response to the display device receiving the tensile failure signal, and to indicate that the stamped part has a wrinkle in response to the display device receiving the wrinkle failure signal.

5. The method according to claim 4, wherein: The SI threshold is 1, and wherein the WI threshold is -1.

6. The method according to claim 1, wherein: Determine using the processor whether the analyzed element is located at the trimmed edge of the stamped part. Assume a linear strain path at each operation, and for each element, calculate the ratio between the incremental small strain and the large strain at each time step i of operation p according to formula (2.1): in, and is the incremental small strain and large strain according to formula (2.2): Among them, the normal anisotropy parameter In uniaxial tension, the critical strain ratio ρ u Approx. So that according to formula (2.3), the analyzed element is determined to be located at the trimmed edge of the stamped part: 0.9p u ≤ρ p (i)≤1.1ρ u (2.3).

7. The method according to claim 1, wherein: Determining, using the processor in response to the processor generating the computer simulation, the SI of the trimmed edge portion includes determining a maximum SI based on a plurality of stretch indices.

8. The method according to claim 1, wherein: Determining the SI of the plane stress portion using the processor in response to the processor generating the computer simulation includes determining the SI according to formula (1.1):

9. The method according to claim 1, wherein: Determining the SI of the trimmed edge portion using the processor in response to the processor generating the computer simulation includes determining the SI according to formula (1.2):

10. A system for producing a die, the die being configured to form a sheet metal blank into a workpiece for a stamped part, the stamped part having a final shape for a motor vehicle, wherein the workpiece has a bead impact portion, a trimmed edge portion, and a plane stress portion, the system comprising: A processor, wherein the processor is configured as: receiving data of at least one of a mold design, a part design, and a stamping process plan associated with the workpiece; generating a computer simulation based on the data; in response to the processor generating the computer simulation, determining a tensile index (SI) of an associated one of the bead-affected portion, the trimmed edge portion, and the plane stress portion of the workpiece; comparing the SI of each of the bead-affected portion, the trimmed edge portion, and the plane stress portion to an SI threshold; as well as generating a tensile failure signal in response to the processor determining that the SI of at least one of the bead-influenced portion, the trimmed edge portion, and the plane stress portion is greater than the SI threshold; determining a wrinkle index of the workpiece in response to the processor generating the computer simulation; comparing the WI with a WI threshold; as well as generating a wrinkle failure signal in response to the processor determining that the WI is less than the WI threshold; receiving changed data of at least one of a changed die design, a changed part design, and a changed stamping process plan associated with the workpiece; generating a modified computer simulation based on the modified data; in response to the processor generating the modified computer simulation, determining a modified SI for an associated one of the bead-affected portion, the trimmed edge portion, and the plane stress portion of the workpiece; as well as generating a stretch acceptance signal in response to the processor determining that one of the SI and the changed SI of each of the bead-affected portion, the trimmed edge portion, and the plane stress portion is not greater than the SI threshold; determining a WI of the workpiece in response to the processor generating a computer simulation of the change; as well as generating a wrinkle acceptance signal in response to the processor determining that one of the WI and the changed WI is less than the WI threshold; as well as a display device electrically coupled to the processor and configured to: In response to the display device receiving the stretch failure signal and / or the wrinkle failure signal, indicating that the workpiece has fracture and / or wrinkle, and prompting a user to input the changed data into the processor; In response to the display device receiving the stretch acceptance signal and / or the wrinkle acceptance signal, indicating that the workpiece does not have the fracture and / or the wrinkle, the processor sends the stretch acceptance signal and / or the wrinkle acceptance signal to a mold manufacturing device, which is used to transform the tool material into the mold associated with one of the SI and the changed SI that is less than the SI threshold and one of the WI and the changed WI that is greater than the WI threshold.

Images