Indoor unstructured component motion virtual simulation method under earthquake scene

Abstract

The invention relates to an indoor unstructured component motion virtual simulation method under an earthquake scene, and the method comprises the steps: carrying out the motion virtual simulation and oscillation virtual simulation of a movable member and a flexible member in an indoor unstructured component under the earthquake scene, and taking all simulation results as final virtual simulation results. Therefore, the dynamic change of the unstructured component in the indoor environment is fully considered, so that the indoor unstructured component motion virtual simulation in the earthquake scene better conforms to the actual situation, the simulation process is reasonable, the virtual simulation result is ensured to well meet the indoor environment scene in the actual earthquake scene, and the simulation accuracy is improved. And a more real and credible virtual simulation result is provided for subsequent virtual reality emergency drilling based on earthquake generation.

Description

Technical Field

[0001] This invention relates to the field of virtual simulation, and more particularly to a virtual simulation method for the motion of unstructured indoor components under earthquake scenarios. Background Technology

[0002] Studies have found that humans spend approximately 90% of their time indoors, in environments such as homes, offices, and other commercial or industrial buildings. Therefore, people living indoors are more vulnerable to various indoor hazards.

[0003] Although modern earthquake-resistant design methods can effectively control the collapse of building structures caused by earthquakes, unstructured components of buildings (suspended ceilings, furniture, shelves, etc.) are still severely damaged, which can seriously block evacuation routes and cause people inside the building to suffer injuries such as fractures and soft tissue contusions, thus delaying people's escape time.

[0004] To conduct simulation studies of earthquake scenarios and provide reference suggestions for escape during earthquake disasters, researchers have already conducted simulation studies on unstructured indoor components under earthquake scenarios. For example, some researchers have proposed a formula to predict the percentage of outdoor areas covered by unstructured component debris based on finite element analysis results, in order to quantify the impact of ground debris density on pedestrian movement. Other researchers have used physics engines to qualitatively simulate changes in unstructured indoor components during earthquakes, emphasizing the realism of the experience for users in virtual reality emergency drills.

[0005] However, existing virtual simulation methods for the movement of unstructured indoor components under earthquake scenarios still have shortcomings: although they consider the changes of unstructured components in earthquake scenarios, they only make qualitative predictions of the changes in unstructured components and do not model the dynamic changes of unstructured components in the indoor environment. As a result, the virtual simulation results cannot show the dynamic changes of the indoor environment under earthquake scenarios and the impact of related changes on the evacuation of people. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a virtual simulation method for the motion of unstructured indoor components under earthquake scenarios.

[0007] The technical solution adopted by this invention to solve the above-mentioned technical problems is: a virtual simulation method for the motion of unstructured indoor components under earthquake scenarios, characterized by comprising the following steps:

[0008] Perform virtual motion simulation of movable components in unstructured indoor structures under earthquake scenarios;

[0009] Virtual simulation of oscillations in seismic scenarios was performed on flexible components in unstructured indoor structures.

[0010] The obtained virtual simulation results of the motion of movable components and the virtual simulation results of the oscillation of flexible components are used as the virtual simulation results of indoor unstructured components under earthquake scenarios.

[0011] Improvedly, in the virtual simulation method for the motion of indoor unstructured components under earthquake scenarios, the process of performing virtual simulation of the motion of movable components in indoor unstructured components under earthquake scenarios includes the following steps:

[0012] Step a1: The acceleration time series from the NGA-West 2 ground motion database is used as the ground acceleration series in the indoor environment under the seismic scenario; where the ground acceleration at time t is labeled as a. g (t), ground acceleration a g (t) The vertical ground acceleration in the direction perpendicular to the ground is denoted as a. v (t), ground acceleration a g (t) The horizontal ground acceleration in the direction parallel to the ground is denoted as a. h (t); t>0;

[0013] Step a2: Using the ground in the indoor environment under the earthquake scenario as a reference frame in a non-inertial reference frame, the relative motion between the movable components and the ground in the indoor environment under the earthquake scenario is analyzed.

[0014] Step a3: Calculate the multiple forces acting on the movable component in an indoor environment under seismic scenarios; where the multiple forces include the seismic influence F of ground acceleration on the movable component. s (t), the gravity G acting on the movable component, and the static friction F acting on the movable component from the ground. f (t), the ground support force N(t) on the movable component, and the air resistance F of the movable component when it moves along the ground. d (t) and the impact force F of other components on the movable member i (t), 1≤i≤I;

[0015] Earthquake Influence F s (t) is decomposed into horizontal seismic force F along the horizontal direction of the ground. h (t) and the vertical seismic force F perpendicular to the ground direction v (t); i is the component number that exerts an impact force on the movable component in the indoor environment under the earthquake scenario, and I is the total number of components that exert an impact force on the movable component in the indoor environment under the earthquake scenario;

[0016] Step a4: Calculate the vertical support resultant force on the movable member when it is located above other objects in the vertical direction; wherein, the vertical support resultant force is the resultant force of the vertical seismic force on the movable member and its own weight.

[0017] Step a5: Calculate the resultant horizontal force on the movable member in the horizontal direction, and obtain the horizontal displacement of the movable member based on the resultant horizontal force.

[0018] Step a6: Obtain the position of the center of gravity of the movable component relative to the contact area between the movable component and the support, and obtain the overturning condition of the movable component based on the position of the center of gravity.

[0019] Step a7: Calculate the air resistance during the fall of the movable component after it detaches from the support below it.

[0020] Step a8: Calculate the final velocity vectors of the movable component and the object after they collide with each other during the motion process.

[0021] Step a9: Based on the calculated vertical support force, horizontal displacement, overturning condition, air resistance during the fall, and final velocity vector of the movable component, perform a virtual simulation of the motion process of the movable component.

[0022] In a further improvement, in the virtual simulation method for the motion of unstructured indoor components under the earthquake scenario, in step a2:

[0023] The seismic influence F of ground acceleration on movable components s (t) is calculated as follows: F s (t)=m·a g (t), where m is the weight of the movable component;

[0024] The ground support force N(t) on the movable component is calculated as follows: N(t) = (G + F) v (t))·cosθ=m·(a v (t)+g)cosθ, where m is the weight of the movable component, g is the acceleration due to gravity, and a is the acceleration perpendicular to the ground. v When the direction of (t) is opposite to the direction of gravitational acceleration g, then a v The value of (t) is negative; the vertical ground acceleration a v When the direction of (t) is in the same direction as the direction of gravitational acceleration g, then a v The value of (t) is positive; θ is the tilt angle of the support located below the movable member and supporting the movable member relative to the horizontal ground.

[0025] Improvedly, in the virtual simulation method for the motion of unstructured indoor components under the earthquake scenario, in step a5, the resultant horizontal force on the movable component in the horizontal direction is calculated, and the horizontal displacement of the movable component is obtained based on the resultant horizontal force; wherein:

[0026] When the horizontal resultant force on the movable component is greater than the maximum static friction force F f At time (t), the movable component produces a horizontal displacement and converts the static friction coefficient into the dynamic friction coefficient;

[0027] The resultant horizontal force on the movable component is F. h (t)·cosθ+G·sinθ, where θ is the inclination angle of the support located below the movable member and supporting the movable member relative to the horizontal ground; and the dynamic friction force F experienced by the movable member during horizontal displacement. f,k (t)=μ k ·N(t), static friction force F f (t)=μ s ·N(t); μ s μ is the static friction coefficient. k is the coefficient of kinetic friction.

[0028] Improvedly, in the virtual simulation method for the motion of unstructured indoor components under the earthquake scenario, in step a6, when the center of gravity of the movable component is located outside the contact area between the movable component and the support, the movable component is made to undergo virtual simulation of overturning motion in the earthquake scenario.

[0029] Furthermore, in the virtual simulation method for the motion of unstructured indoor components under the earthquake scenario, in step a7, the air resistance during the fall of the movable component after it detaches from its underlying support is calculated as follows:

[0030]

[0031] Among them, F d (t) represents the air resistance experienced by the movable component during its fall, ρ represents the air density in the indoor environment where the movable component is located, and c d Let v(t) be the air resistance coefficient experienced by the movable component during its fall, v(t) be the velocity of the object during its fall, and A be the projected cross-sectional area of ​​the movable component in the direction of its vertical velocity.

[0032] Improvedly, in the virtual simulation method for the motion of unstructured indoor components under the earthquake scenario, in step a8, the final motion velocity includes a final horizontal motion velocity in the horizontal direction and a final vertical motion velocity perpendicular to the horizontal direction; wherein:

[0033] The calculation method for the final horizontal velocity of the movable component and the object after they collide with each other during the motion process is as follows:

[0034]

[0035] Where v1' is the final horizontal velocity of the movable component after the collision, v'2 is the final horizontal velocity of the object colliding with the movable component after the collision, m1 is the mass of the movable component, m2 is the mass of the object colliding with the movable component, v1 is the velocity of the movable component before the collision, v2 is the velocity of the object colliding with the movable component before the collision, and C R The coefficient of recovery.

[0036] Improvedly, in the virtual simulation method for the motion of unstructured indoor components under the earthquake scenario, the actual final velocity vector of the movable component in three-dimensional space after a collision is denoted as v:

[0037] v p = (v·n)n, v r =vv p ;

[0038] v1 = ||v p ||,v f =v′1n p +v r ;

[0039] Among them, v p v is the projected velocity of the object on the unit normal vector n, where n is the unit normal vector at the point of contact when the movable component collides with the object. r v is the orthogonal velocity of the object along the unit normal vector n; v1 is the velocity of the movable component before the collision. f Let v1' be the actual velocity of the object in three-dimensional space after the collision, and n be the final horizontal velocity of the movable component after the collision. p To be related to the projection speed v p Unit vectors in the same direction.

[0040] Further improvements include the following steps in the virtual simulation method for the motion of unstructured indoor components under earthquake scenarios:

[0041] Step b1: The end portion of the flexible component is considered as a forced harmonic oscillator subjected to external random forces;

[0042] Step b2: Construct a vibration motion model of the end of the flexible component; the constructed vibration motion model is as follows:

[0043]

[0044] x t =x t-1 +v t-1 △t, v t =v t-1 +at-1 △t; t>0, x0=0, y0=0;

[0045]

[0046] Where m0 is the mass of the end portion of the flexible member, k is the elastic coefficient of the flexible member, and x t Let be the displacement of the flexible member at time t, and c be the viscous damping coefficient of the flexible member, -kx t For the restoring force of flexible components, The damping force of the flexible component, Let x be the velocity of the flexible component, F0 be the projected component of the seismic force along the oscillation direction of the flexible component, and x be the velocity of the flexible component. t-1 Let v be the displacement of the flexible component at time t-1. t Let be the velocity of the flexible component at time t, and Δt be the time interval between time t and time t-1; a t Let a be the acceleration of the flexible component at time t. t-1 Let a be the acceleration of the flexible component at time t-1; g Let f be the ground acceleration vector, and let f be the unit vector of the frontal orientation of the flexible component.

[0047] Furthermore, in the virtual simulation method for the motion of unstructured indoor components under the earthquake scenario, the displacement of the end of the flexible component after overall bending at time t is calculated as follows:

[0048]

[0049] Where, d t Let be the displacement of the end of the flexible component after overall bending at time t, and let h be any point p on the flexible component. A At time t, the vertical height relative to the horizontal ground, L is the vertical length of the flexible component in the direction perpendicular to the horizontal ground, and x is the vertical height of the component relative to the horizontal ground. t Let θ be the displacement of the flexible component at time t. t Point p on the flexible component A The bending angle at time t.

[0050] Further improvements include, in this invention, the virtual simulation method for the motion of unstructured indoor components under earthquake scenarios further comprising:

[0051] Pre-construct the physical interaction relationship between movable and flexible components in unstructured indoor components;

[0052] Virtual simulation of the physical interaction between movable and flexible components under earthquake scenarios; and...

[0053] The virtual simulation results of the physical interaction between movable and flexible components are used as part of the virtual simulation results of indoor unstructured components under the earthquake scenario.

[0054] Compared with the prior art, the advantages of the present invention are as follows:

[0055] First, the virtual simulation method for the motion of unstructured indoor components under earthquake scenarios in this invention performs virtual motion simulations of movable components and virtual oscillation simulations of flexible components under earthquake scenarios, respectively. The resulting virtual simulation results of the movable component motion and the flexible component oscillation are then used as the virtual simulation results for unstructured indoor components under earthquake scenarios. This invention fully considers the dynamic changes of unstructured components in the indoor environment, making the virtual simulation of the motion of unstructured indoor components under earthquake scenarios more realistic and reasonable. The simulation process is reasonable, ensuring that the virtual simulation results can well meet the indoor environmental scenarios under actual earthquakes, thus providing more realistic and reliable virtual simulation results for subsequent virtual reality emergency drills based on earthquakes.

[0056] Secondly, the virtual simulation method for the motion of unstructured indoor components under earthquake scenarios further pre-constructs the physical interaction relationship between movable and flexible components in the unstructured indoor components, performs virtual simulation of the physical interaction between the movable and flexible components under earthquake scenarios, and then uses the virtual simulation results of the physical interaction between the movable and flexible components as part of the virtual simulation results of the unstructured indoor components under earthquake scenarios. This will be more in line with the motion patterns in real earthquake scenarios. Attached Figure Description

[0057] To more clearly illustrate the specific embodiments of this disclosure, the accompanying drawings used in the specific embodiments will be briefly introduced below.

[0058] Figure 1 This is a schematic diagram of the virtual simulation method for the motion of unstructured indoor components under earthquake scenarios in an embodiment of the present invention;

[0059] Figure 2 This is a schematic diagram of the motion state of the movable component in an embodiment of the present invention;

[0060] Figure 3 This is a schematic diagram of the bending of the flexible component in an embodiment of the present invention;

[0061] Figure 4 This is a motion simulation diagram of the movable component in an embodiment of the present invention; wherein, Figure 4 Figure a in the diagram shows the initial state of the movable component. Figure 4 Figure b in the diagram is a schematic diagram of the final state of the movable component after its movement;

[0062] Figure 5 This is a schematic diagram of the oscillation simulation of the flexible component in an embodiment of the present invention; wherein, Figure 5 Figure a in the diagram shows the initial state of the flexible component. Figure 5 Figure b in the diagram shows the state where the end of the flexible component has shifted 10cm to the right. Figure 5 Figure c in the diagram shows the state where the end of the flexible component has shifted 20cm to the left.

[0063] Figure 6 This is a schematic diagram of an indoor scene under an earthquake scenario in an embodiment of the present invention; wherein, Figure 6 Figure a in the diagram is a schematic diagram of the initial state of the indoor scene. Figure 6 Figure b in the diagram is a schematic diagram of an indoor scene during the process of the product falling. Figure 6 Figure c in the diagram is a schematic diagram of the indoor scene when the shelf is oscillating. Figure 6 The diagram d in the figure is a schematic diagram of the final scene state of the indoor scene;

[0064] Figure 7 This is a schematic diagram of the state of three sets of shelves and goods used in an embodiment of the present invention to analyze the effects of PGA (Peak Ground Acceleration), shelf oscillation, and the mass of movable components.

[0065] Figure 8 This diagram illustrates the percentage of movable components that have fallen off under different PGA (Programme of Gauge).

[0066] Figure 9 A schematic diagram showing the percentage of movable components that fell off under different earthquake conditions;

[0067] Figure 10 A schematic diagram showing the distribution of movable components falling in different directions during different earthquakes;

[0068] Figure 11 Schematic diagram showing the fall of different movable components during different earthquakes;

[0069] Figure 12 This is a schematic diagram of the shelf oscillation displacement curve in an embodiment of the present invention;

[0070] Figure 13 This is a schematic diagram illustrating the average displacement of fallen goods under different PGA conditions in an embodiment of the present invention. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0073] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0074] This embodiment provides a virtual simulation method for the motion of unstructured indoor components under earthquake scenarios. Specifically, see [link to documentation]. Figure 1 As shown, the virtual simulation method for the motion of unstructured indoor components under earthquake scenarios in this embodiment includes the following steps 1 to 3:

[0075] Step 1: Perform virtual motion simulation of movable components in unstructured indoor structures under earthquake scenarios;

[0076] Step 2: Perform virtual oscillation simulation of flexible components in indoor unstructured parts under earthquake scenarios;

[0077] Step 3: Use the obtained virtual simulation results of the motion of movable components and the virtual simulation results of the oscillation of flexible components as the virtual simulation results of indoor unstructured components under earthquake scenarios.

[0078] Specifically, in step 1 of this embodiment, see Figure 2 As shown, the process of performing virtual motion simulation of movable components in an earthquake scenario for unstructured indoor parts includes the following steps a1 to a9:

[0079] Step a1: The acceleration time series from the NGA-West 2 ground motion database is used as the ground acceleration series in the indoor environment under the seismic scenario; where the ground acceleration at time t is labeled as a. g (t), ground acceleration a g (t) The vertical ground acceleration in the direction perpendicular to the ground is denoted as a. v (t), ground acceleration a g (t) The horizontal ground acceleration in the direction parallel to the ground is denoted as a. h (t); t>0;

[0080] Step a2 involves using the ground in the indoor environment under the earthquake scenario as a reference frame in a non-inertial reference system to analyze the relative motion between the movable components and the ground in the indoor environment under the earthquake scenario; specifically, in this embodiment:

[0081] The seismic influence F of ground acceleration on movable components s (t) is calculated as follows: F s (t)=m·a g (t), where m is the weight of the movable component;

[0082] The ground support force N(t) on the movable component is calculated as follows: N(t) = (G + F) v (t))·cosθ=m·(a v (t)+g)cosθ, where m is the weight of the movable component and g is the acceleration due to gravity; and the acceleration perpendicular to the ground is a. v When the direction of (t) is opposite to the direction of gravitational acceleration g, then a v The value of (t) is negative; the vertical ground acceleration a v When the direction of (t) is in the same direction as the direction of gravitational acceleration g, then a v The value of (t) is a positive number; θ is the tilt angle of the support located below the movable member and supporting the movable member relative to the horizontal ground;

[0083] Step a3: Calculate the multiple forces acting on the movable component in an indoor environment under seismic scenarios; where the multiple forces include the seismic influence F of ground acceleration on the movable component. s (t), the gravity G acting on the movable component, and the static friction F acting on the movable component from the ground. f (t), the ground support force N(t) on the movable component, and the air resistance F of the movable component when it moves along the ground. d (t) and the impact force F of other components on the movable member i (t), 1≤i≤I;

[0084] Earthquake Influence F s (t) is decomposed into horizontal seismic force F along the horizontal direction of the ground. h (t) and the vertical seismic force F perpendicular to the ground direction v (t); i is the component number that exerts an impact force on the movable component in the indoor environment under the earthquake scenario, and I is the total number of components that exert an impact force on the movable component in the indoor environment under the earthquake scenario;

[0085] Step a4: Calculate the vertical support resultant force on the movable member when it is located above other objects in the vertical direction; wherein, the vertical support resultant force is the resultant force of the vertical seismic force on the movable member and its own weight.

[0086] Step a5: Calculate the resultant horizontal force on the movable member in the horizontal direction, and obtain the horizontal displacement of the movable member based on the resultant horizontal force; wherein, in this embodiment, the resultant horizontal force on the movable member in the horizontal direction is calculated, and the horizontal displacement of the movable member is obtained based on the resultant horizontal force; wherein:

[0087] When the resultant horizontal force on the movable component is greater than the maximum static friction force F f At time (t), the movable component produces a horizontal displacement and converts the static friction coefficient into the dynamic friction coefficient;

[0088] The resultant horizontal force on the movable component is F. h (t)·cosθ+G·sinθ, the dynamic friction force F experienced by the movable component during horizontal displacement. f,k (t)=μ k ·N(t), F f (t)=μ s ·N(t); μ s μ is the static friction coefficient. k Let θ be the coefficient of kinetic friction, and θ be the angle of inclination of the support located below the movable member and supporting the movable member relative to the horizontal ground.

[0089] Step a6: Obtain the position of the center of gravity of the movable component relative to the contact area between the movable component and the support, and obtain the overturning condition of the movable component based on the position of the center of gravity.

[0090] In step a6, when the center of gravity of the movable component is located outside the contact area between the movable component and the support, a virtual simulation is performed to make the movable component overturn in an earthquake scenario.

[0091] Step a7: Calculate the air resistance during the fall of the movable component after it detaches from its lower support; the calculation method for the air resistance during the fall of the movable component after it detaches from its lower support is as follows:

[0092]

[0093] Among them, F d (t) represents the air resistance experienced by the movable component during its fall, ρ represents the air density in the indoor environment where the movable component is located, and c d Let v(t) be the air resistance coefficient experienced by the movable component during its fall, v(t) be the velocity of the object during its fall, and A be the projected cross-sectional area of ​​the movable component in the direction of its vertical velocity.

[0094] Step a8: Calculate the final velocity vectors of the movable component and the object after they collide with each other during the motion process.

[0095] Step a9: Based on the calculated vertical support force, horizontal displacement, overturning condition, air resistance during the fall, and final velocity vector of the movable component, perform a virtual simulation of the motion process of the movable component.

[0096] It should be noted that in step a8 of this embodiment, the aforementioned final motion speed includes a final horizontal motion speed in the horizontal direction and a final vertical motion speed perpendicular to the horizontal direction; wherein:

[0097] The final horizontal velocity of both the movable component and the object after a collision during motion is calculated as follows:

[0098]

[0099] Where v1' is the final horizontal velocity of the movable component after the collision, v'2 is the final horizontal velocity of the object colliding with the movable component after the collision, m1 is the mass of the movable component, m2 is the mass of the object colliding with the movable component, v1 is the velocity of the movable component before the collision, v2 is the velocity of the object colliding with the movable component before the collision, and C R The coefficient of recovery.

[0100] The true final velocity vector of the movable component in three-dimensional space after a collision is denoted as v:

[0101] v p = (v·n)n, v r =vv p ;

[0102] v1 = ||v p ||,v f =v′1n p +v r ;

[0103] Among them, v p v is the projected velocity of the object on the unit normal vector n, where n is the unit normal vector at the point of contact when the movable component collides with the object. r v is the orthogonal velocity of the object along the unit normal vector n; v1 is the velocity of the movable component before the collision. f Let v1' be the actual velocity of the object in three-dimensional space after the collision, and n be the final horizontal velocity of the movable component after the collision. p To be related to the projection speed v p Unit vectors in the same direction.

[0104] In addition, in this embodiment, step 2, the process of performing a virtual simulation of oscillations under an earthquake scenario on the flexible components in the indoor unstructured parts, includes the following steps:

[0105] Step b1: The end portion of the flexible component is considered as a forced harmonic oscillator subjected to external random forces;

[0106] Step b2: Construct a vibration motion model of the end of the flexible component; the constructed vibration motion model is as follows:

[0107]

[0108] x t =x t-1 +v t-1 △t, v t =v t-1 +a t-1 △t; t>0, x0=0, y0=0;

[0109]

[0110] Where m0 is the mass of the end portion of the flexible member, k is the elastic coefficient of the flexible member, and x t Let be the displacement of the flexible member at time t, and c be the viscous damping coefficient of the flexible member, -kx t For the restoring force of flexible components, For the damping force of flexible components, Let x be the velocity of the flexible component, F0 be the projected component of the seismic force along the oscillation direction of the flexible component, and x be the velocity of the flexible component. t-1 Let v be the displacement of the flexible component at time t-1. t Let be the velocity of the flexible component at time t, and Δt be the time interval between time t and time t-1; a t Let a be the acceleration of the flexible component at time t. t-1 Let a be the acceleration of the flexible component at time t-1; g Let f be the ground acceleration vector, and let f be the unit vector of the frontal orientation of the flexible component.

[0111] Additionally, see Figure 3 As shown, in this embodiment, the displacement of the end of the flexible member after overall bending at time t is calculated as follows:

[0112]

[0113] Where, d t Let f be the displacement of the end of the flexible member after overall bending at time t, and let h be any point p on the flexible member. AAt time t, the vertical height relative to the horizontal ground, L is the vertical length of the flexible component in the direction perpendicular to the horizontal ground, and x is the vertical height of the component relative to the horizontal ground. t Let θ be the displacement of the flexible component at time t. t Point p on the flexible component A The bending angle at time t.

[0114] Of course, depending on actual needs, the virtual simulation method for the motion of indoor unstructured components under earthquake scenarios in this embodiment further includes: pre-constructing the physical interaction relationship between movable and flexible components in indoor unstructured components; performing virtual simulation of the physical interaction between movable and flexible components under earthquake scenarios; and using the virtual simulation results of the physical interaction between movable and flexible components as part of the virtual simulation results of indoor unstructured components under earthquake scenarios.

[0115] To verify the simulation effect of the virtual simulation method for the motion of unstructured indoor components under earthquake scenarios in this embodiment, a computer simulation was also performed. The specific details are as follows:

[0116] Parameter settings: Constants for movable components (μs = 0.4, μk = 0.3, CR = 0.3); constants for flexible components (mo = 10 kg, k = 1600 N / m, c = 20 N·s / m); air density ρ in the indoor environment where the movable component is located is 1.29 kg / m³. 3 .

[0117] Import the 3D model of the movable component into the Unity scene (e.g., Figure 4 (as shown in (a)) and set the corresponding object mass and drag coefficients according to the model's properties and shape. Finally, apply seismic force to the movable components based on the acceleration time series data. The final state of the movable components is shown in [the image / data]. Figure 4 In (b), most of the goods fell to the ground due to the earthquake force.

[0118] Additionally, select shelves in a supermarket setting (such as...). Figure 5 (a) serves as an example of simulating flexible components and demonstrates physical interaction with movable components. Through the proposed vibration motion model, the shelf deforms under seismic forces, with goods located at higher positions being more affected. For goods of similar size, those stacked, irregularly shaped, and with a higher center of gravity are more prone to movement (e.g., ...). Figure 5 (b) As the curvature of the shelf increases, the degree of change of the goods on the shelf increases (e.g., as shown in (b)); Figure 5 (c) is shown.

[0119] Finally, the simulations of movable and flexible components are integrated together, such as... Figure 6As shown, the various goods in the scene are movable components, while the fixed shelves at the bottom are flexible components, thus forming an indoor supermarket scene. Under the action of seismic forces, the shelves begin to vibrate, the goods move and begin to fall, and the quantity and area of ​​goods piled up on the ground continuously increase. Compared with double-sided shelves, single-sided shelves, because their backs are supported, have a relatively smaller amplitude of vibration, and more goods are retained on the shelves.

[0120] Since acceleration time series data is used as input data for environmental simulation, its PGA attribute has a significant impact on changes in the indoor scene. This embodiment uses peak ground acceleration as an amplitude modulation index to adjust the seismic data, thereby setting the seismic intensity. Simultaneously, to analyze the impact of shelf oscillations and the mass of the goods themselves on the movement of the goods, this embodiment uses Northridge ground motion data and sets up three shelves containing goods (e.g., ...). Figure 7 The following comparisons were made (as shown). In the first group, the shelves did not deform; in the second group, the shelves oscillated under seismic forces; and in the third group, while considering shelf oscillation, the mass of all goods on the shelves was magnified 20 times. Additionally, we arranged shelves and goods facing four different directions to reduce the impact of changes in the direction of ground acceleration.

[0121] This embodiment also analyzes the impact of the above factors on the movement of movable components by measuring the percentage of items dropped in each group, such as... Figure 8 As shown in the diagram, it can be observed that the item drop in the first group has two stages. When the PGA is less than 0.18g, none of the items on the shelf fall to the ground. However, when the PGA is greater than 0.18g, some of the stacked goods begin to fall to the ground, and the number of items falling increases with the intensity of the earthquake. Because different goods have different shapes, their corresponding PGAs at the start of movement are also different, so the drop curve does not have a significant inflection point near 0.4g. The percentage curves of item drop in the second and third groups are similar, indicating that for movable components of the same shape and center of gravity, their own mass has little impact on their movement. This is consistent with the principle that the mass of an object is irrelevant when determining its movement state. By comparing the item drop curves of the first and second groups, goods fall earlier as the shelf moves, and the shelf oscillations even enhance the ability of the shelf to promote item drop as the earthquake intensity increases. Therefore, the seismic force plays a major role in the movement of movable components, and the shelf oscillations can promote the goods to leave the equilibrium state earlier. It should also be noted that, since the number of goods placed at high positions in the experiment was still relatively small, the difference between the two sets of curves was small under low earthquake intensity.

[0122] Acceleration time series data itself also has a significant impact on the motion of movable components; therefore, we selected data from three earthquake events with similar magnitudes—Northridge, Kobe, and Imperial Valley—for simulation. Figure 9 As shown, the start times of item falling differed across the three earthquake events. Furthermore, in the Northridge and Imperial Valley events, the falling of goods was primarily concentrated within a single timeframe, while in the Kobe event, the falling goods were distributed across multiple timeframes. The number of items falling from shelves oriented differently was also influenced by the earthquake data, such as... Figure 10 As shown, the number of objects falling in the four directions was roughly the same in the Kobe and Imperial Valley events, indicating that the effects of seismic waves on objects in different directions were roughly similar. However, although the total number of objects falling in the Notheidge event was less than in the other two events, the distribution of the number of objects falling in the four directions was very irregular.

[0123] See Figure 11 As shown, the arrangement and quantity of goods of different shapes vary, resulting in different distributions of them on the ground. Smaller goods are arranged in greater numbers, resulting in a larger accumulation area and higher density, while relatively larger goods are arranged in fewer numbers, resulting in a lower density of accumulation on the ground nearby. However, due to the shape of the goods themselves, they may displace a greater distance.

[0124] See Figure 12 As shown, it can be observed that under seismic forces, the oscillation period of the unsupported shelving is relatively stable, while the oscillation amplitude varies with the ground acceleration. In contrast, the oscillation period of the supported shelving is unstable, and its oscillation frequency is lower than that of the unsupported shelving; the only similarity between the two is their maximum offset distance. This indicates that back support can, to some extent, suppress the oscillating motion of flexible components in a seismic environment.

[0125] See Figure 13 As shown, shelf oscillations cause goods to fall earlier. Due to the intensity of the earthquake, unsupported shelves significantly accelerated the fall of goods, resulting in greater horizontal displacement. Providing support at the back of the shelf effectively reduces the impact of oscillations on product movement. When the PGA is low, primarily high-level stacked goods fall, leading to a rapid increase in average horizontal displacement. However, as the PGA increases, lower-level stacked goods also fall, causing a slight decrease in average horizontal displacement. When the PGA exceeds 0.4g, exceeding the set static friction coefficient, other types of goods also begin to fall, and the average horizontal displacement increases again. In the control group (shelves without oscillation), the average horizontal displacement of falling goods did not show a significant decline.

[0126] Although preferred embodiments of the present invention have been described in detail above, it should be clearly understood that various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A virtual simulation method for the motion of unstructured indoor components under earthquake scenarios, characterized in that, Includes the following steps: Perform virtual motion simulation of movable components in unstructured indoor structures under earthquake scenarios; Virtual simulation of oscillations in seismic scenarios was performed on flexible components in unstructured indoor structures. The obtained virtual simulation results of the motion of movable components and the virtual simulation results of the oscillation of flexible components are used as the virtual simulation results of indoor unstructured components under earthquake scenarios.

2. The virtual simulation method for the motion of unstructured indoor components under earthquake scenarios according to claim 1, characterized in that, The process of performing virtual motion simulation of movable components in unstructured indoor structures under earthquake scenarios includes the following steps: Step a1: The acceleration time series from the NGA-West 2 ground motion database is used as the ground acceleration series in the indoor environment under the seismic scenario; where the ground acceleration at time t is labeled as a. g (t), ground acceleration a g (t) The vertical ground acceleration in the direction perpendicular to the ground is denoted as a. v (t), ground acceleration a g (t) The horizontal ground acceleration in the direction parallel to the ground is denoted as a. h (t); t>0; Step a2: Using the ground in the indoor environment under the earthquake scenario as a reference frame in a non-inertial reference frame, the relative motion between the movable components and the ground in the indoor environment under the earthquake scenario is analyzed. Step a3: Calculate the multiple forces acting on the movable component in an indoor environment under seismic scenarios; where the multiple forces include the seismic influence F of ground acceleration on the movable component. s (t), the gravity G acting on the movable component, and the static friction F acting on the movable component from the ground. f (t), the ground support force N(t) on the movable component, and the air resistance F of the movable component when it moves along the ground. d (t) and the impact force F of other components on the movable member i (t), 1≤i≤I; Earthquake Influence F s (t) is decomposed into horizontal seismic force F along the horizontal direction of the ground. h (t) and the vertical seismic force F perpendicular to the ground direction v (t); i is the component number that exerts an impact force on the movable component in the indoor environment under the earthquake scenario, and I is the total number of components that exert an impact force on the movable component in the indoor environment under the earthquake scenario; Step a4: Calculate the vertical support resultant force on the movable member when it is located above other objects in the vertical direction; wherein, the vertical support resultant force is the resultant force of the vertical seismic force on the movable member and its own weight. Step a5: Calculate the resultant horizontal force on the movable member in the horizontal direction, and obtain the horizontal displacement of the movable member based on the resultant horizontal force. Step a6: Obtain the position of the center of gravity of the movable component relative to the contact area between the movable component and the support, and obtain the overturning condition of the movable component based on the position of the center of gravity. Step a7: Calculate the air resistance during the fall of the movable component after it detaches from the support below it. Step a8: Calculate the final velocity vectors of the movable component and the object after they collide with each other during the motion process. Step a9: Based on the calculated vertical support force, horizontal displacement, overturning condition, air resistance during the fall, and final velocity vector of the movable component, perform a virtual simulation of the motion process of the movable component.

3. The virtual simulation method for the motion of unstructured indoor components under earthquake scenarios according to claim 2, characterized in that, In step a2: The seismic influence F of ground acceleration on movable components s (t) is calculated as follows: F s (t)=m·a g (t), where m is the weight of the movable component; The ground support force N(t) on the movable component is calculated as follows: N(t) = (G + F) v (t))·cosθ=m·(a v (t)+g)cosθ, where m is the weight of the movable component and g is the acceleration due to gravity; and the acceleration perpendicular to the ground is a. v When the direction of (t) is opposite to the direction of gravitational acceleration g, then a v The value of (t) is negative; the vertical ground acceleration a v When the direction of (t) is in the same direction as the direction of gravitational acceleration g, then a v The value of (t) is positive; θ is the tilt angle of the support located below the movable member and supporting the movable member relative to the horizontal ground.

4. The virtual simulation method for the motion of unstructured indoor components under earthquake scenarios according to claim 3, characterized in that, In step a5, the resultant horizontal force on the movable member in the horizontal direction is calculated, and the horizontal displacement of the movable member is obtained based on the resultant horizontal force; wherein: when the resultant horizontal force on the movable member is greater than the maximum static friction force F f At time (t), the movable component produces a horizontal displacement and converts the static friction coefficient into the dynamic friction coefficient; The resultant horizontal force on the movable component is F. h (t)·cosθ+G·sinθ, the dynamic friction force F experienced by the movable component during horizontal displacement. f,k (t)=μ k ·N(t), F f (t)=μ s ·N(t); μ s μ is the static friction coefficient. k Let θ be the coefficient of kinetic friction, and θ be the angle of inclination of the support located below the movable member and supporting the movable member relative to the horizontal ground.

5. The virtual simulation method for the motion of unstructured indoor components under earthquake scenarios according to claim 3, characterized in that, In step a6, when the center of gravity of the movable component is located outside the contact area between the movable component and the support, a virtual simulation of the movable component overturning motion is performed in an earthquake scenario.

6. The virtual simulation method for the motion of unstructured indoor components under earthquake scenarios according to claim 3, characterized in that, In step a7, the air resistance during the fall of the movable component after it detaches from its support is calculated as follows: Among them, F d (t) represents the air resistance experienced by the movable component during its fall, ρ represents the air density in the indoor environment where the movable component is located, and c d Let v(t) be the air resistance coefficient experienced by the movable component during its fall, v(t) be the velocity of the object during its fall, and A be the projected cross-sectional area of ​​the movable component in the direction of its vertical velocity.

7. The virtual simulation method for the motion of unstructured indoor components under earthquake scenarios according to claim 3, characterized in that, In step a8, the final motion speed includes a final horizontal motion speed in the horizontal direction and a final vertical motion speed perpendicular to the horizontal direction; wherein: The calculation method for the final horizontal velocity of the movable component and the object after they collide with each other during the motion process is as follows: Among them, v1 ' Let v be the final horizontal velocity of the movable component after the collision. ' 2 represents the final horizontal velocity of the object colliding with the movable component after the collision; m1 is the mass of the movable component; m2 is the mass of the object colliding with the movable component; v1 is the velocity of the movable component before the collision; v2 is the velocity of the object colliding with the movable component before the collision; C R The coefficient of recovery.

8. The virtual simulation method for the motion of unstructured indoor components under earthquake scenarios according to claim 7, characterized in that, The actual final velocity vector of the movable component after the collision in three-dimensional space is denoted as v: v p =(v·n)n,v r =vv p ; v1=||v p ||,v f =v'1n p +v r ; Among them, v p v is the projected velocity of the object on the unit normal vector n, where n is the unit normal vector at the point of contact when the movable component collides with the object. r v is the orthogonal velocity of the object along the unit normal vector n; v1 is the velocity of the movable component before the collision. f Let v'1 be the actual velocity of the object in three-dimensional space after the collision, and n be the final horizontal velocity of the movable component after the collision. p To be related to the projection speed v p Unit vectors in the same direction.

9. The virtual simulation method for the motion of unstructured indoor components under earthquake scenarios according to claim 8, characterized in that, Also includes: Pre-construct the physical interaction relationship between movable and flexible components in unstructured indoor components; Virtual simulation of the physical interaction between movable and flexible components under earthquake scenarios; as well as, The virtual simulation results of the physical interaction between movable and flexible components are used as part of the virtual simulation results of indoor unstructured components under the earthquake scenario.

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