Head-side airbag chamber volume optimization system for hard contact avoidance

Abstract

This invention relates to the field of testing and simulation technology, and discloses a head-side airbag chamber volume optimization system for hard-contact avoidance. The system includes: first, establishing a three-dimensional collision protection zone along the direction of occupant head impact, defining the protected target chamber and adjacent compensation chambers; then, extracting the oblique tension constraint model of the target chamber, and constructing multiple sets of internal suture displacement volume configuration schemes while keeping the outer perimeter boundary unchanged; next, calculating the corrected effective thickness based on the phase loss caused by the oblique constraint and the collision avoidance energy absorption requirements, and redistributing the volume parameters of each chamber; finally, mapping the target volume parameter set to the actual fabric outline and performing bench verification. This invention effectively avoids thickness reduction offset caused by internal straps and suture restraint, ensuring effective buffer travel within the collision avoidance channel.

Description

Technical Field

[0001] This invention relates to the field of test simulation technology, and more specifically, to a head-side airbag chamber volume optimization system for hard contact avoidance. Background Technology

[0002] In the field of vehicle passive safety development, side curtain airbags are mainly used to provide a buffer layer between the occupant's head and rigid interior components such as the window edges, B-pillars, and C-pillar trim panels during side collisions. Existing strategies for developing side airbag chamber volumes are typically based on maximizing two-dimensional planar coverage and total volume. In specific engineering iteration phases, when crash simulation assessments reveal insufficient buffer margin in the dummy's head contact area, the conventional approach is often to directly increase the design volume of the chamber corresponding to that contact point.

[0003] However, side curtain airbags incorporate multiple chambers, non-inflatable seam blocking, and multi-directional restraint straps. During actual gas expansion and deployment, the effective buffer thickness of a local chamber along the direction of occupant head impact is affected not only by the gas supply but also by the combined constraints of adjacent seams, connecting chambers, and the tension of the diagonal restraint straps. When the design volume of the target chamber increases and exceeds the expansion critical point determined by the aforementioned factors, the increased gas volume translates into in-plane tensile tension on the airbag surface, potentially causing the chamber to flatten along the plane of the window, or even causing the airbag to shift and bend towards the vehicle body. This anomalous attenuation phenomenon—an increase in volume leading to a decrease in the normal effective buffer thickness—makes traditional local volume-increasing iteration methods prone to failure, resulting in difficulties in converging hard-contact injury indicators during whole-vehicle crash testing. Summary of the Invention

[0004] This invention provides a head-side airbag chamber volume optimization system for hard contact avoidance, which solves the technical problems mentioned in the background art.

[0005] This invention provides a head-side airbag chamber volume optimization system for hard contact avoidance, applicable to vehicles containing rigid side structures and head-side airbags with fixed peripheral boundaries, configured to perform: Set the test head model and its collision motion direction, and define the energy absorption threshold for avoiding hard contact; Establish a three-dimensional protection zone for head hard contact to define the target head chambers and adjacent compensation chambers; Extract the oblique tensile force constraint feature model of the target head cavity; Without changing the outer peripheral fixed boundary, construct multiple sets of chamber volume parameter configuration schemes for the target head chamber and the adjacent compensation chamber; The target chamber volume after constraint correction is calculated using the oblique tension constraint feature model, and the volume is allocated under the condition of meeting the energy absorption requirement threshold to obtain the target chamber volume parameter set; The target volume parameter set of the chamber is mapped to the optimized chamber geometric boundary; The optimized chamber geometry boundary was verified by performing a collision unfolding simulation. After successful verification, the target volume parameters of the target head cavity and the adjacent compensation cavity are output.

[0006] Beneficial effects include: This invention can identify and compensate for abnormal airbag shrinkage caused by the oblique restraint of straps and seams without changing the fixed boundary of the airbag or the internal components of the vehicle. By establishing a three-dimensional collision protection zone and introducing an oblique tension constraint model for volume redistribution under constrained conditions, this invention not only ensures effective buffer thickness in the direction of occupant head impact, truly converting the increased gas volume into collision protection margin, but also avoids the risk of airbag collapse and displacement to the outside caused by blindly increasing the volume of a single chamber, steadily improving the upper limit of occupant protection in side collision conditions. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the head hard contact avoidance scenario and protection zone delineation according to the present invention; Figure 2 This is a schematic diagram illustrating the attenuation of effective buffer thickness caused by the oblique tensile force constraint of the present invention; Figure 3 This is a schematic diagram of the volume redistribution and boundary optimization of the target chamber and the adjacent compensation chamber of the present invention. Detailed Implementation

[0008] The following combination Figures 1 to 3 The specific embodiments of the present invention will be further described below. It should be understood that the embodiments described herein are used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention; without departing from the concept of the present invention, those skilled in the art can make equivalent substitutions for data sources, parameter values, solution methods and output formats based on differences in vehicle platforms, airbag structures, simulation software or manufacturing processes.

[0009] In this embodiment, the head-side airbag chamber volume optimization system for hard-contact avoidance can be deployed in a vehicle passive safety simulation platform, a finite element preprocessing platform, an airbag product data management platform, or a combination of the above platforms. The system includes a protected area construction module, a chamber identification module, a constraint feature extraction module, a candidate volume generation module, an effective thickness correction module, a volume allocation optimization module, a geometric boundary generation module, a simulation verification module, and a parameter output module. Each module can be implemented by a computer processor reading program instructions from memory, or it can be implemented collaboratively through a data interface between simulation software, geometric modeling software, and product data management software.

[0010] The input data for this embodiment includes the three-dimensional geometric data of the vehicle side panel rigid structure, the planar deployment diagram of the head side airbag, the three-dimensional deployment model of the head side airbag, the coordinates of the internal seams, the coordinates of the tether connection, the cavity connectivity, the mass of the test head mold, the motion trajectory of the test head mold, the inflation curve of the gas generator, the airbag folding envelope, and the in-vehicle installation space data. The system output data includes the target head cavity volume, the volume of adjacent compensation cavities, the internal seam update coordinates, the coordinates of the smooth transition section, the outline of the cut piece or the forming boundary of the integrated weave, the simulation verification results, and the drawing number corresponding to the manufacturing end.

[0011] Example 1: Combination Figure 1 The protected area construction module first reads the three-dimensional geometric model of the vehicle's side hard structure. This vehicle side hard structure may include the upper edge of the window, the inner door panel, the B-pillar trim, the C-pillar trim, the door frame boundary, and other rigid or near-rigid structures that may form hard contact during lateral head movements. The system discretizes the surfaces of these structures into a hard collision surface mesh. This mesh can use triangular patches, quadrilateral patches, or a combination of both. The side length of the patches can be set to 5 mm to 15 mm, preferably 10 mm, to balance the accuracy of hard contact boundary recognition and computational load.

[0012] The protected area construction module acquires the central motion trajectory of the test head model under the target collision condition, and sweeps the three-dimensional shape of the test head model along this central motion trajectory to form the head model motion envelope. The test head model can be a standard head model, a finite element dummy head model, or a head replacement model processed with equivalent mass and shape. The system further extracts the normal velocity vector of the test head model toward the vehicle side hard structure, and determines the direction of the collision motion of this vector. Subsequently, the system continues to sweep the head model motion envelope along the collision motion direction, extracts the spatial region where the swept body intersects with, penetrates, or has a minimum gap less than a preset safety gap threshold with the hard collision surface mesh, and defines this spatial region as a candidate anti-collision space channel.

[0013] In one alternative implementation, the candidate collision avoidance space channel has dynamic time boundaries. Its start time can be set when the head-side airbag begins to form an accessible surface on the occupant side, and its end time can be set when the test head model's velocity first drops below a specified residual velocity, or when the head model reaches its maximum indentation depth or the collision simulation terminates. By using these time boundaries, the system can eliminate invalid spaces that do not participate in hard-contact avoidance before the airbags deploy or after the head model has stopped, making the constructed protection zone more closely match the actual protection requirements during a collision.

[0014] The candidate anti-collision space channel is not directly equivalent to the chamber area of ​​the airbag that needs adjustment. The system projects the candidate anti-collision space channel in the reverse direction of the collision motion onto the occupant-side deployment surface of the head-side airbag to obtain the anti-collision safety zone projection surface. The anti-collision safety zone projection surface is used to represent the airbag surface area that needs to provide effective buffer stroke in the head mold intrusion direction. If the candidate anti-collision space channel forms multiple separated areas after being projected onto the curved surface, the system can mark the multiple separated areas separately according to the overlap ratio of each area with the head mold motion trajectory, the distance with the hard collision surface grid, and the preset safety gap threshold.

[0015] After obtaining the projection surface of the collision avoidance safety zone, the chamber identification module traverses the chamber boundaries of the head-side airbag. Airbag chambers that overlap, intersect, or have a center distance less than a preset threshold with the projection surface of the collision avoidance safety zone are defined as target head chambers; chambers that share internal sutures, gas communication channels, or are directly coupled in inflation timing with the target head chambers are defined as adjacent compensation chambers. By treating the target head chambers and adjacent compensation chambers as local volume redistribution objects, the effective buffer thickness within the collision avoidance channel can be optimized in a targeted manner without changing the fixed outer boundary of the airbag and the in-vehicle installation space.

[0016] Example 2: Combination Figure 2 The constraint feature extraction module reads the two-dimensional planar unfolded diagram of the head-side airbag and marks the inflation boundary, non-inflatable area seams, and pull strap connection lines in the two-dimensional planar unfolded diagram. The inflation boundary is the outer or inner closed boundary that defines the area where gas can enter; the non-inflatable area seams are linear structures that make the inner and outer fabric layers adhere together and block local inflation; the pull strap connection lines are the fixed tracks of the solid pull straps on the fabric layers that limit the excessive inflation of the airbag along the normal direction.

[0017] The system maps the inflatable boundaries, non-inflatable area seams, and tension strap connections from two-dimensional coordinates to the three-dimensional airbag surface based on the node correspondence, mesh unfolding relationship, or surface parametric mapping relationship between the two-dimensional planar unfolded diagram and the three-dimensional unfolded model. For each mapped seam or tension strap connection, the system generates multiple sampling points at a preset sampling interval and records its spatial location, chamber number, line segment length, line segment direction, and relative position to the projection surface of the anti-collision safety zone. The sampling interval can be set according to the airbag mesh size, for example, no more than twice the spacing between adjacent finite element nodes.

[0018] To avoid including structural lines far from the head contact area in the calculation, the system uses distance filtering to determine effective constraint segments. Specifically, non-inflatable area sutures and strap connections that fall within the projection plane of the anti-collision safety zone are identified as effective constraint segments; segments that do not fall within the projection plane of the anti-collision safety zone but whose shortest distance from it is no greater than the local height of the target head chamber deployment are also identified as effective constraint segments. The local height of the target head chamber deployment can be taken as the maximum geometric span of the chamber perpendicular to the main axis of the airbag on the planar deployment diagram, with an example range of 150 mm to 300 mm.

[0019] For each candidate suture or strap connection, the system calculates the minimum Euclidean distance from its sampling point to the boundary of the anti-collision safety zone projection plane or the geometric center line. When any sampling point falls within the anti-collision safety zone projection plane, or when the minimum distance is not greater than the local height of the target head cavity deployment, the system includes the line segment in the set of effective constraint lines. The extension direction of the line segment can be determined by the spatial difference vector between adjacent sampling points, or by the axial tangent vector in the tangent plane of the three-dimensional curved surface. The angle between the line segment and the collision motion direction can be obtained by inverse calculation using the cosine of the angle between the extension direction vector and the collision motion direction vector. The length of the inflatable boundary, the length of the non-inflatable suture, and the projection length of the strap can all be obtained by summing the segment lengths between adjacent sampling points; the corresponding cavity number can be obtained by matching the closed cavity boundaries or cavity mesh identifiers on both sides of the line segment.

[0020] For the Each chamber is equipped with This is the length of the inflation boundary of the chamber. For the first Effective non-inflatable suture length, The angle between the direction of the suture extension and the direction of the impact motion. For the first Effective traction belt projection length, Let be the angle between the direction of the pull belt and the direction of the collision motion. The system will... The oblique stretch reduction coefficient of each chamber Defined as: ; The above Used to characterize the degree to which intracavitary sutures and traction bands weaken the normal bulging ability. The larger the value, the easier it is for the increased gas volume to be converted into in-plane stretching, lateral flattening, or offset towards the vehicle body, rather than into effective buffer thickness in the direction of the head mold pressing. The system will... The spatial topological relationship of the effective constraint line segments, the chamber number to which the effective constraint line segments belong, and the projection surface position of the anti-collision safety zone are encapsulated together to form the oblique tensile constraint feature model of the target head chamber.

[0021] Example 3: The candidate volume generation module reads the initial 3D mesh of the target head cavity and adjacent compensation cavities, and obtains the initial cavity volume of each cavity by integrating the closed space volume. For airbags manufactured using a sewing process, the volume can be estimated based on the cut panel boundaries, internal seams, and inflation thickness, and then corrected by a three-dimensional unfolding model. For airbags manufactured using an integrated weaving process, the volume can be calculated based on the interlacing boundaries of the double-layer fabric and the chamber pressure unfolding shape.

[0022] While maintaining the fixed outer perimeter boundary of the airbag, the gas generator inlet, the top edge fixing point, and the strap anchoring point unchanged, the system selects the internal seam adjacent to the projected plane of the anti-collision safety zone as the adjustable boundary. The system sets displacement variables along the local normal direction of this internal seam. . When the value is positive, the corresponding boundary of the target head cavity moves in the direction of volume increase; When the value is negative, the boundary of the target head cavity moves in the direction of volume reduction. For adjacent compensation cavities sharing an internal suture, the displacement causes their volume change direction to be opposite to that of the target head cavity, thereby satisfying the local total volume constraint.

[0023] To balance safety performance and manufacturing stability, In discrete sets You can select from the middle, or from a continuous interval. Internal sampling. The minimum distance between the seam and gas communication channel, the strap anchoring area, the fabric reinforcement, the folded envelope, and the vehicle interior installation space can be determined. The increase in volume of the target head chamber and the decrease in volume of the adjacent compensation chamber are not required to be absolutely equal under all three-dimensional deformation conditions, but rather they should satisfy a compensation relationship within a preset volume error range.

[0024] In one alternative implementation, the system calculates the change in the projected area of ​​the candidate chamber based on the chamber boundary before and after the internal suture movement. The candidate volume change was estimated by combining the local effective bulge height. If a 3D mesh recalculation method is used, the system regenerates the cavity closure mesh and calculates the volume after each movement of the internal sutures until the error between the candidate volume and the target volume does not exceed a preset volume error threshold. This volume error threshold can be determined based on the product design tolerance, for example, set to 1% to 3% of the target volume.

[0025] The system is based on different Multiple candidate chamber volume parameter configuration schemes are generated, and corresponding airbag finite element mesh profiles are generated simultaneously. During mesh profile generation, the outer fixed boundary nodes remain stationary, while the inner fabric nodes smoothly migrate according to the boundary after seam displacement, thus obtaining a simulation verification model that matches the candidate volume schemes. If a candidate mesh exhibits element flipping, closed gas communication channels, shifted anchor points, or interference with the vehicle's installation space, the system will discard the corresponding candidate scheme.

[0026] Example 4: The effective thickness correction module calculates the normal effective buffer thickness for each candidate chamber volume. Let the first... The effective projected area of ​​each chamber within the collision avoidance safety zone is: The maximum bulging depth in the normal direction is .when The unit is square millimeter. When the unit is millimeters and the volume unit is cubic centimeters, the critical volume for effective normal expansion is... Represented as: ; This indicates that before the chamber is significantly constrained by oblique tension, the candidate inflation volume can be effectively converted into the upper limit of the normal inflation thickness. Regarding the candidate inflation volume... Ideal buffer thickness Represented as: ; when No more than At that time, the newly added gas volume is mainly used to form the normal buffer thickness; when Exceed At this time, the excess portion is more easily restrained by sutures and straps, transforming into in-plane stretch. The system will control the relative overflow amount. Defined as: ; The system is based on the diagonal tension reduction factor. and relative overflow Calculate the effective thickness attenuation coefficient : ; in, Represents the natural exponential function. Actual normal effective buffer thickness after oblique constraint correction. for: ; The volume allocation optimization module is based on the test head mold quality. Normal collision velocity Upper limit of buffer support force and residual compaction thickness margin Determine the minimum effective buffer thickness Collision kinetic energy and Represented as: ; ; in, The unit is kilogram. The unit is meters per second. The unit is Newton. and The unit is millimeters. This minimum effective cushioning thickness is used to characterize the minimum effective stroke that the airbag needs to provide along the headform insertion direction without hard contact and without exceeding the upper limit of the cushioning support force.

[0027] The system uses candidate volumes for each chamber. The decision variables are defined under constraints including the total airbag volume, upper and lower limits of the chamber volume, maximum displacement of internal sutures, minimum width of the gas communication channel, and non-interference constraint of the folded envelope. The total volume constraint can be expressed as: ; The upper and lower limits of the chamber volume constraints can be expressed as: ; The internal suture displacement constraint can be expressed as: ; objective function It can be in the following form: ; in, For the first Each chamber within the collision-avoidance safety zone bears the area weight of head contact. This represents the volume fluctuation penalty coefficient. The first term penalizes insufficient effective thickness, and the second term limits volume fluctuation relative to the initial design. The system can use quadratic programming, gradient search, enumeration search, or simulation calibration table lookup to find candidate volume combinations with smaller objective functions, and then determine these candidate volume combinations as the target volume parameter set for the chamber.

[0028] To illustrate the above calculation relationship, in a set of simulation calibration data, the effective projected area of ​​the target head cavity... The maximum bulging depth in the normal direction is 40,000 square millimeters. If it is 75 mm, then It is 3000 cubic centimeters. If the diagonal stretching reduces the coefficient... The value is 0.85, when the candidate inflation volume is... When the volume is 3600 cubic centimeters, the system calculates... It is 90 mm. It is 0.2. Approximately 0.967, the corrected actual normal effective buffer thickness. It is approximately 87 mm. This example demonstrates that the candidate volume does not always translate linearly into the effective buffer thickness and requires correction in conjunction with oblique constraints.

[0029] Example 5: The geometric boundary generation module establishes an airbag chamber inventory and writes the chamber target volume parameter groups into the inventory according to the chamber number. For chambers with a target volume larger than the initial volume, the system moves the internal suture adjacent to the anti-collision safety zone in a direction away from the geometric center of the chamber; for chambers with a target volume smaller than the initial volume, the system moves the internal suture in a direction closer to the geometric center of the chamber.

[0030] When determining the direction of internal suture movement, the system can first calculate the two-dimensional tangent vector at the discrete coordinate points of the internal suture, and then rotate this two-dimensional tangent vector by 90 degrees to obtain the candidate normal direction. Based on the relative position between this normal direction and the geometric center of the target head cavity, the system determines the volume increase and decrease directions. For curved surface unfolding models, the system can also calculate the local normal direction within the three-dimensional curved surface tangent plane and project this direction back into the two-dimensional unfolded diagram to ensure consistency between the two-dimensional pattern adjustment and the three-dimensional unfolding effect.

[0031] In one alternative implementation, the system is based on the target volume. With initial volume The difference between the two values ​​is used to calculate the internal suture displacement. The system first provides an initial displacement value. Based on this displacement, candidate boundaries are generated and the chamber volume is recalculated. .like and The difference between them exceeds the preset volume error threshold. The system adjusts the displacement and repeats the calculation until the following condition is met: ; in, The iteration count is given. This inverse calculation process can be achieved using contour offset area integration, finite element mesh volume recalculation, binary search, or a pre-established calibration table of suture displacement and chamber volume change. Through this process, the system can stably transform abstract target volume parameters into manufacturable internal suture coordinates.

[0032] After the internal suture moves, geometric breaks may form between its two ends and the unmoved suture. The system incorporates a smooth transition section between the endpoints of the moved internal suture and the initial non-inflatable area suture. This smooth transition section can be generated using a cubic Bézier curve, a circular arc transition, or a spline curve. The starting tangent of the smooth transition section aligns with the moved internal suture, and the ending tangent aligns with the initial non-inflatable area suture, thereby avoiding sharp corners, reversals, or excessively dense local sutures.

[0033] After generating the smooth transition section, the system verifies the distances between the smooth transition section and the gas communication channel, the tension anchor reinforcement, the outer fixed boundary, and adjacent seams. If any distance is less than a preset manufacturing gap threshold, the system reduces the internal seam displacement, changes the curvature of the transition section, or reselects an adjustable internal seam. For areas near the gas generator inlet, the system prioritizes moving internal seam segments that do not alter the early gas flow topology to avoid abnormal gas propagation timing due to localized volume expansion.

[0034] The system further reads the initial airbag folding envelope and the in-vehicle installation space. For split-stitched airbags, the system converts the updated internal seams and inflation boundaries into planar fabric outlines and recalculates the edge allowances of the fabric pieces; for one-piece woven airbags, the system converts the updated boundaries into coordinates of the interlacing boundaries of the two-layer fabric. Subsequently, the system converts the optimized chamber geometry into a three-dimensional finite element state to verify whether there is any penetration or spatial interference between it and the initial folding envelope and the in-vehicle installation space.

[0035] Example 6: The simulation verification module constructs an airbag simulation bench model that includes the roof liner, B-pillar trim, C-pillar trim, window openings, side panel sheet metal parts, gas generator mounting points, top edge fixing clips, and interior seam opening paths. The system imports the optimized chamber geometry into this bench model and completes the airbag folding, installation, and boundary constraint settings according to the actual assembly posture. The airbag folding can adopt the same rolling, pressing, or layering folding methods as in the real vehicle, and the contact relationship between the folding layers is preserved in the simulation model.

[0036] During the deployment simulation phase, the system simulates the gas inflow process based on the gas generator mass flow rate curve, gas temperature curve, and chamber connectivity, allowing the head-side airbag to expand through the interior trim gaps and reach the projection surface of the collision safety zone. This process can be achieved using a controlled volume gas model or a fluid-structure interaction (FSI) computational model. The system also defines fabric self-contact, contact between the fabric and interior trim components, contact between the fabric and the hard impact surface mesh, and friction parameters to represent potential slippage, obstruction, bending, and local hysteresis phenomena during airbag deployment.

[0037] During the headform insertion phase, the system assigns initial velocity boundary conditions to the test headform at a predetermined moment when the airbag deployment is complete, causing the test headform to be inserted into the deployed head-side airbag along the collision motion direction. The initial position of the test headform can be set on the reverse extension line of the collision motion direction, and its center of mass or geometric center should be matched with the head trajectory in the target collision condition. The system can set the test headform as a rigid body model or as a finite element model with equivalent mass and inertia.

[0038] The system records the actual minimum effective buffer thickness during the indentation process, the minimum distance between the test head mold and the hard impact surface mesh, whether the head mold undergoes geometric penetration, whether the target head chamber collapses and bends towards the sidewall rigid structure of the vehicle, and whether the airbag detaches from the projection plane of the collision avoidance safety zone. The actual minimum effective buffer thickness can be obtained by extracting the instantaneous normal distance between the foremost node of the test head mold and the hard impact surface mesh directly in front of it, and taking the minimum value over the entire indentation time history. Whether the head mold crosses the hard impact surface mesh can be determined by whether spatial penetration or cumulative penetration occurs between the head mold node and the hard impact surface mesh. Whether the target head chamber collapses and bends can be determined by considering the deflection angle of the normal of the outer fabric of the target head chamber, local stress concentration areas, and shrinkage deformation near the seams.

[0039] When the actual minimum effective buffer thickness is greater than or equal to If the test head model does not cross the hard impact surface grid, the target head cavity does not experience instability and collapse towards the rigid side structure of the vehicle, and there is no structural interference within the optimized airbag deployment path and folding envelope, the system determines that the target volume parameter set of the cavity has passed verification. If any condition is not met, the system marks the parameter set as unqualified and returns to the volume allocation optimization module to reselect candidate volumes, adjust the internal seam displacement range, or redetermine adjacent compensation cavities.

[0040] Example 7: After successful verification, the parameter output module creates the airbag chamber geometry drawing, product design parameter table, and airbag chamber outline drawing number. Using the airbag chamber list as an index, the system extracts the target head chamber volume value and adjacent compensation chamber volume values ​​from the verified target volume parameter group and writes them into the product design parameter table.

[0041] The system marks the location of each target chamber volume value on the airbag chamber geometry drawing and saves the updated coordinates of the internal sutures, the coordinates of the smooth transition section, the width of the gas communication channel, and the applicable fabric outline number. To ensure consistency between the simulation and manufacturing ends, the system writes the airbag chamber outline drawing number into the file attributes or header field of the product design parameter table. When the manufacturing end calls the product design parameter table, it matches the corresponding airbag chamber geometry drawing by the drawing number; if the numbers do not match, the system outputs a version mismatch warning and stops generating the corresponding manufacturing data.

[0042] As a result, the anti-hard contact buffer requirements of the target head chamber, the volume adjustment margin of adjacent compensation chambers, the change of internal suture position, the update of the cut piece outline, and the collision simulation verification results are uniformly bound into the same set of engineering data, realizing a closed-loop transfer from simulation optimization to manufacturing layout.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any equivalent substitutions, combinations, or improvements made to module settings, parameter values, solution algorithms, simulation models, or manufacturing output methods within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A head-side airbag chamber volume optimization system for hard contact avoidance, applied to vehicles containing rigid side structures and head-side airbags with fixed peripheral boundaries, characterized in that, Configured for execution: Set the test head model and its collision motion direction, and define the energy absorption threshold for avoiding hard contact; Establish a three-dimensional protection zone for head hard contact to define the target head chambers and adjacent compensation chambers; Extract the oblique tensile force constraint feature model of the target head cavity; Without changing the outer peripheral fixed boundary, construct multiple chamber volume parameter configuration schemes for the target head chamber and the adjacent compensation chamber; The target chamber volume after constraint correction is calculated using the oblique tension constraint feature model, and the volume is allocated under the condition of meeting the energy absorption requirement threshold to obtain the target chamber volume parameter set; The target volume parameter set of the chamber is mapped to the optimized chamber geometric boundary; The optimized chamber geometry boundary was verified by performing a collision unfolding simulation. After successful verification, the target volume parameters of the target head cavity and the adjacent compensation cavity are output.

2. The head-side airbag chamber volume optimization system for hard contact avoidance according to claim 1, characterized in that, Establish a three-dimensional protection zone for head hard contact to define the target head chambers and adjacent compensation chambers, including: The rigid structural surface of the vehicle side wall is divided into a rigid collision surface grid; The envelope of the center motion trajectory of the test head mold is swept along the direction of the collision motion to form a candidate anti-collision space channel that intersects with the grid of the hard collision surface. The candidate anti-collision space channel is projected onto the occupant-side surface of the deployed head-side airbag to obtain the anti-collision safety zone projection surface. The head-side airbag has an internal suture and a gas communication channel. The airbag chamber covered by the projection surface of the anti-collision safety zone is defined as the target head chamber. The adjacent airbag chambers that share the internal suture or the gas communication channel with the target head chamber are defined as the adjacent compensation chambers.

3. The head-side airbag chamber volume optimization system for hard contact avoidance according to claim 2, characterized in that, Extracting the oblique tensile constraint feature model of the target head cavity includes: Obtain a planar unfolded view of the head-side airbag, and mark the inflation boundary, non-inflatable area sutures, and traction strap connection lines on the planar unfolded view; The inflation boundary, the non-inflatable area seam, and the tether connection line are mapped onto the surface of the deployed three-dimensional airbag. Record the characteristic parameters of the non-inflatable area suture and the traction strap connection line that fall within the projection surface of the anti-collision safety zone, or whose shortest distance from the projection surface of the anti-collision safety zone is not greater than the local height of the target head cavity deployment. The characteristic parameters include the suture extension direction within the airbag deployment surface, the angle with the collision motion direction, the shortest distance from the geometric center line of the projection surface of the anti-collision safety zone, the length of the inflation boundary, the length of the non-inflatable area suture, the projection length of the traction strap, and the corresponding cavity number. Generate a stretching feature vector line containing the aforementioned feature parameters, and synthesize the stretching feature vector line into the oblique tensile force constraint feature model of the target head cavity.

4. The head-side airbag chamber volume optimization system for hard contact avoidance according to claim 3, characterized in that, Without altering the fixed outer perimeter boundary, construct multiple chamber volume parameter configuration schemes for the target head chamber and the adjacent compensation chamber, including: Obtain the initial chamber volumes of the target head chamber and the adjacent compensation chamber; Based on the initial chamber volume, the internal suture is offset outward along the outer contour boundary of the anti-collision safety zone projection plane corresponding to the target head chamber to form a chamber expansion contour. The internal suture is offset inward along the outer contour boundary corresponding to the adjacent compensation chamber to form an equal volume reduction contour. The target head cavity is configured into three states: a volume reduction state, a volume reference state, and a volume increase state. Adjacent compensation cavities are configured into compensation volume states with equal changes and opposite directions of increase and decrease. The corresponding airbag simulation verification model outlines are generated using the three configuration states and the compensation volume configuration state, respectively.

5. The head-side airbag chamber volume optimization system for hard contact avoidance according to claim 4, characterized in that, The target chamber volume after constraint correction is calculated using the aforementioned oblique tension constraint characteristic model, and a set of target chamber volume parameters is obtained by volume allocation under the condition of satisfying the aforementioned energy absorption requirement threshold, including: The oblique tensile reduction coefficient is calculated using the non-inflatable area seam length, the pull strap projection length, the inflatable boundary length, and the angle with the direction of the collision motion from the aforementioned characteristic parameters. Obtain the effective projected area and maximum normal inflatable depth of the airbag chamber, and establish the critical volume for effective normal expansion. Obtain candidate inflation volumes, and determine ideal buffer thickness based on the candidate inflation volumes and the effective projected area of ​​the airbag chamber; determine effective thickness attenuation coefficient by combining the relative overflow amount of the candidate inflation volumes exceeding the normal effective expansion critical volume with the oblique stretch reduction coefficient; apply the effective thickness attenuation coefficient to correct the ideal buffer thickness to obtain the actual normal effective buffer thickness; The mass, normal collision velocity, upper limit of buffer support force, and residual compaction thickness margin of the test head mold are obtained. The collision kinetic energy is calculated and the minimum effective buffer thickness corresponding to the energy absorption requirement threshold is derived. While maintaining the total volume constraint of the airbag, the volume allocation is performed to obtain the optimal allocation value, which constitutes the target volume parameter set of the chambers, based on the sum of the actual normal effective buffer thicknesses of each chamber meeting the minimum effective buffer thickness condition.

6. The head-side airbag chamber volume optimization system for hard contact avoidance according to claim 5, characterized in that, Mapping the target volume parameter set of the chamber to the optimized chamber geometric boundary includes: Establish an airbag chamber list and write the target volume parameter set of the chamber into the airbag chamber list; According to the direction of increase or decrease of the volume of each airbag chamber relative to the initial chamber, the position of the internal suture is moved along the normal direction of the internal suture adjacent to the projection plane of the anti-collision safety zone. Smooth transition sections are provided at both ends of the internal suture after the position is moved, so that the internal suture after the position is moved can be connected back to the non-inflatable area suture in the initial state. Obtain the initial airbag folding envelope and in-vehicle installation space; generate an updated planar cutout outline or a one-piece woven airbag outline as the optimized chamber geometry boundary, and verify that there is no spatial structural interference between the optimized chamber geometry boundary and the initial airbag folding envelope and the in-vehicle installation space.

7. The head-side airbag chamber volume optimization system for hard contact avoidance according to claim 6, characterized in that, The optimized chamber geometry boundary is subjected to collision unfolding simulation for final verification, including: Construct an airbag simulation bench model that includes the opening path of interior gaps; The optimized chamber geometry is imported into the airbag simulation bench model. Simulated gas inflow causes the head-side airbag to pass through the interior trim gaps and deploy onto the projection surface of the collision safety zone; Drive the test head mold to press into the deployed head side airbag along the collision motion direction; Record the actual minimum effective buffer thickness during the pressing process, whether the test head mold crosses the hard collision surface grid, and whether the target head cavity collapses and bends towards the side of the vehicle's hard structure, thereby confirming whether the target volume parameter set of the cavity is qualified.

8. The head-side airbag chamber volume optimization system for hard contact avoidance according to claim 7, characterized in that, After successful verification, the target volume parameters of the target head cavity and the adjacent compensation cavity are output, including: Create geometric drawings of the airbag chamber, product design parameter tables, and numbered outline drawings of the airbag chamber; Using the airbag chamber list as an index, the target chamber volume value is extracted from the qualified chamber target volume parameter group; Mark the location of the airbag chamber corresponding to each target chamber volume value on the geometric drawing of the airbag chamber; The extracted volume of the target head cavity and the corresponding volume of the adjacent compensation cavity are written into the product design parameter table to form the final output target volume parameter. The corresponding airbag chamber outline drawing number is output synchronously to establish data consistency between the manufacturing end and the simulation end.

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