A method for analyzing longitudinal impact performance of liquid in a tank and braking performance of a tank truck

Abstract

The application discloses a kind of tank liquid longitudinal impact performance analysis method and liquid tank truck braking performance analysis method, by the tank liquid longitudinal impact performance analysis method including using spring mass model to construct tank liquid longitudinal impact equivalent mechanical model, and liquid tank truck braking performance analysis method includes the tank liquid longitudinal impact performance analysis method, realize to the tank liquid longitudinal impact performance of any kind of transverse fender arranged in tank truck braking performance can be quickly, efficiently analyzed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of analysis of liquid longitudinal impact performance in a tank body, in particular to the technical field of analysis of braking performance of a liquid tank truck, and in particular to a method for analyzing liquid longitudinal impact performance in a tank body and a method for analyzing braking performance of a liquid tank truck. BACKGROUND

[0002] With the development of logistics, long-distance transportation of various liquid materials has become a realistic demand for modern economic development, and liquid tank trucks are widely used in road transportation of liquid goods.

[0003] Due to the fluid nature of liquid goods, during braking of a liquid tank truck, the liquid goods in the tank body will produce impact along the longitudinal axis of the tank body under the action of braking force, which seriously affects the braking efficiency of the liquid tank truck. In order to reduce the impact of liquid longitudinal impact on the braking efficiency of the liquid tank truck, the industry mainly uses transverse fender plates arranged in the tank body to suppress liquid impact; however, the types of transverse fender plates arranged in the tank body are various, and the effects of different fender plates are also different. However, there is currently a lack of effective simulation detection methods to detect the impact of liquid along the longitudinal axis of the tank body under the action of braking force for different types of tank bodies; and there is also a lack of effective simulation detection methods to detect the improvement of the transverse fender plate on the braking efficiency of the liquid tank truck; currently, real vehicle tests or simulation methods are generally used for research, and such research methods lack universality, and if the type of fender plate, the shape of the tank body, the size of the tank body, the filling rate of the liquid goods in the tank body, etc. are changed, new tests need to be conducted, and the detection period is long and the cost is high.

[0004] Therefore, how to invent a liquid tank truck braking efficiency analysis method with universality, which can quickly and efficiently analyze the braking performance of a liquid tank truck with any type of transverse fender plate arranged in the tank body, has become a technical problem in the field. SUMMARY

[0005] To solve the above technical problems, the present application provides a method for analyzing liquid longitudinal impact performance in a tank body and a method for analyzing braking performance of a liquid tank truck, which uses a spring-mass model to construct an equivalent mechanical model of liquid longitudinal impact in the tank body, and the method for analyzing braking performance of a liquid tank truck includes the method for analyzing liquid longitudinal impact performance in the tank body, which can quickly and efficiently analyze the braking performance of a liquid tank truck with any type of transverse fender plate arranged in the tank body.

[0006] According to one aspect of the present application, a method for analyzing liquid longitudinal impact performance in a tank body is provided, comprising the following steps: constructing an equivalent mechanical model of liquid longitudinal impact in the tank body based on a spring-mass model; classifying the tank body; obtaining variable parameter information and system parameter information of different types of tank bodies;

[0007] According to the variable parameter information of different categories of tank bodies, system parameter information and longitudinal impact equivalent mechanical model of liquid in the tank body, the displacement x1 of the equivalent longitudinal impact liquid relative to the tank body with time and the equivalent longitudinal impact liquid mass m str The longitudinal impact performance of the liquid in the tank body is characterized.

[0008] The equivalent longitudinal impact liquid is a liquid whose center of mass moves along the displacement direction of the tank body.

[0009] The displacement x1 of the equivalent longitudinal impact liquid relative to the tank body is the displacement of the center of mass of the equivalent longitudinal impact liquid along the displacement direction of the tank body; and the equivalent longitudinal impact liquid mass m str does not change with time; and the equivalent longitudinal impact liquid mass is only related to the shape of the tank body, the arrangement of the baffle and the liquid filling ratio in the tank body.

[0010] The variable parameter information is directly obtained during the movement or braking of the tank body; and the system parameter information is the parameter information calculated by combining the shape of the tank body, the arrangement of the baffle and the variable parameter information.

[0011] Compared with the prior art, the present application has the following beneficial effects: the calculation of the displacement x1 of the equivalent longitudinal impact liquid relative to the tank body with time is realized by using the spring mass model to construct the longitudinal impact equivalent mechanical model of the liquid in the tank body.

[0012] By obtaining the variable parameter information of different categories of tank bodies, the liquid longitudinal impact strength of different categories of tank bodies under different liquid filling ratios can be simulated and detected.

[0013] By calculating the displacement x1 of the equivalent longitudinal impact liquid relative to the tank body with time and the equivalent longitudinal impact liquid mass m str , the influence of the impact of the liquid along the longitudinal axis of the tank body on the braking effect of the tank body under the action of the braking force can be effectively reflected.

[0014] And the calculation of the equivalent longitudinal impact liquid mass, the equivalent longitudinal impact liquid impact force and the time variation curve of the center of mass of the equivalent longitudinal impact liquid during the braking process of the tank body can be realized, and the maximum value of the equivalent longitudinal impact liquid impact force and the time sequence data of the center of mass of the equivalent longitudinal impact liquid can also be calculated; since the displacement of the center of mass of the impact liquid along the longitudinal direction of the tank body has a great impact on the tank body, and the displacement of the impact liquid along the vertical direction of the tank body is small and has almost no impact on the tank body, the displacement of the equivalent longitudinal impact liquid relative to the tank body is the displacement of the center of mass of the impact liquid along the displacement direction of the tank body.

[0015] Further, the tank body categories include a communication type tank body and a partition type tank body; the communication type tank body includes an A-type communication type tank body and a B-type communication type tank body; the partition type tank body includes an A-type partition type tank body and a B-type partition type tank body;

[0016] The communication type tank body is a tank body without a wave breaker intersecting with a movement or force direction of the tank body, so that liquid shaking is not affected by the wave breaker, and liquid longitudinal shaking is not inhibited, and the liquid longitudinal shaking direction is parallel to the movement direction of the tank body;

[0017] The partition type tank body is a tank body in which a wave breaker without a manhole, a flow hole or other apertures is arranged according to the requirement of the number of the wave breaker in the national standard, so that the tank body is divided into multiple completely disconnected cabins; the liquid in different cabins of the partition type tank body is completely not communicated, and the liquid shaking is maximally inhibited;

[0018] The A-type communication type tank body is a communication type tank body with a width-height ratio of 1.5;

[0019] The B-type communication type tank body is a communication type tank body with a width-height ratio of 2;

[0020] The A-type partition type tank body is a partition type tank body with a width-height ratio of 1.5;

[0021] The B-type partition type tank body is a partition type tank body with a width-height ratio of 2;

[0022] The width-height ratio is a ratio of the width to the height of the tank body cross section; preferably, the tank body cross section is an ellipse, and the width-height ratio is a ratio of the long semi-axis to the short semi-axis of the tank body cross section.

[0023] The beneficial effects of the above further scheme are that by classifying the tank body, the main effects of the tank body cross section and the wave breaker arrangement on liquid impact can be distinguished, so that the spring mass model established can further accurately analyze the liquid longitudinal impact intensity in different tank bodies.

[0024] Further, the variable parameter information includes m c , π, a; wherein, m c is a mass of the liquid stored in the tank body; π is a liquid filling ratio in the tank body; a is a longitudinal acceleration obtained by the tank body under external excitation; the liquid filling ratio is defined as a ratio of the liquid surface height to the tank body height; preferably, the liquid filling ratio changes from 0.1 to 0.9 with a change step of 0.1, so as to cover most of the liquid filling levels of the tank; the longitudinal acceleration obtained by the tank body under external excitation changes from 0.1g to 1.0g with a change step of 0.1g;

[0025] Further, the system parameter information includes k and c; the k is the equivalent longitudinal impact liquid spring stiffness; and the c is the equivalent longitudinal impact liquid dimensionless damping coefficient.

[0026] The beneficial effect of the further scheme is that the liquid filling level of the tank is measured by the liquid filling ratio; the external excitation of the liquid cargo in most cases is measured by the longitudinal acceleration of the tank under the external excitation.

[0027] The variable parameters and the system parameters are used to calculate the liquid longitudinal impact strength related data of the tank under different liquid storage mass, liquid filling ratio in the tank, and longitudinal acceleration of the tank under the external excitation.

[0028] Further, the liquid longitudinal impact equivalent mechanical model includes a spring mass model dynamics equation and an equivalent longitudinal impact liquid mass and tank liquid storage mass ratio calculation formula.

[0029] The dynamics equation of the spring mass model is:

[0030]

[0031] wherein, is the second derivative of the equivalent longitudinal impact liquid displacement x1 relative to the tank;

[0032] is the first derivative of the equivalent longitudinal impact liquid displacement x1 relative to the tank;

[0033] m sta is the equivalent static liquid mass;

[0034] The equivalent longitudinal impact liquid mass and tank liquid storage mass ratio calculation formula includes:

[0035] (m str / m c )1=-0.6319π 3 +0.4973π 2 +0.1596π+0.089;

[0036] (m str / m c )2=2.1770π 3 -7.0441π 2 +4.9615π-0.1812;

[0037] (m str / m c )3=-2.9710π 3 +3.6615π 2-0.9185π+0.1722;

[0038] (m str / m c )4=1.2005π 3 -5.6508π 2 +4.4139π-0.1068;

[0039] wherein, (m str / m c )1 is the ratio of the equivalent longitudinal impact liquid mass in the A type connected tank to the liquid mass stored in the tank;

[0040] (m str / m c )2 is the ratio of the equivalent longitudinal impact liquid mass in the A type divided tank to the liquid mass stored in the tank;

[0041] (m str / m c )3 is the ratio of the equivalent longitudinal impact liquid mass in the B type connected tank to the liquid mass stored in the tank;

[0042] (m str / m c )4 is the ratio of the equivalent longitudinal impact liquid mass in the B type divided tank to the liquid mass stored in the tank.

[0043] The beneficial effects of the above further scheme are that, by the equivalent longitudinal impact liquid mass to liquid mass stored in the tank ratio calculation formula and the kinetic equation of the spring mass model, combined with the variable parameter information and system parameter information, the displacement x1 of the equivalent longitudinal impact liquid relative to the tank over time and the equivalent longitudinal impact liquid mass m str , equivalent static liquid mass m sta are calculated under different liquid filling ratios and different external excitations of the tank.

[0044] Further, the spring stiffness k of the equivalent longitudinal impact liquid is calculated by the formula: k=ω 2 ﹒m c ; wherein ω is the free oscillation angular frequency of the equivalent longitudinal impact liquid.

[0045] The beneficial effects of the above further scheme are that the calculation method of the spring stiffness k of the equivalent longitudinal impact liquid is realized.

[0046] Further, ω includes ω1, ω2, ω3, ω4;

[0047] ω1 is the free oscillation angular frequency of the equivalent longitudinal impact liquid in the A type connected tank;

[0048] ω2 is the free oscillation angular frequency of the equivalent longitudinally impacted liquid in the A type divided tank;

[0049] ω3 is the free oscillation angular frequency of the equivalent longitudinally impacted liquid in the B type connected tank;

[0050] ω4 is the free oscillation angular frequency of the equivalent longitudinally impacted liquid in the B type divided tank;

[0051] ω1 = -0.0641π 2 -0.5239π + 3.6147;

[0052] ω2 = -0.0335π 2 -0.0927π + 4.4521;

[0053] ω3 = -0.0945π 2 -0.7993π + 4.2041;

[0054] ω4 = -0.0550π 2 -0.3940π + 5.3758.

[0055] The beneficial effect of the above further scheme is that the free oscillation angular frequency ω of the equivalent longitudinally impacted liquid under the condition of different tanks and different liquid filling ratios is calculated.

[0056] Further, the calculation formula of the dimensionless damping coefficient c of the equivalent longitudinally impacted liquid is: the c is calculated by the following formula:

[0057] Wherein, ζ includes ζ1, ζ2, ζ3, ζ4;

[0058] ζ1 = -0.0114π 2 + 0.0046π + 0.2337;

[0059] ζ2 = 0.0338π 2 - 0.2783π + 0.5596;

[0060] ζ3 = 0.0289π 2 - 0.1759π + 0.6747;

[0061] ζ4 = -0.0361π 2 - 0.2495π + 0.5454;

[0062] ζ1 is the dimensionless damping coefficient of the equivalent longitudinally impacted liquid in the A type connected tank;

[0063] ζ2 is a non-dimensional damping coefficient of an equivalent longitudinal impact liquid in the A type divided tank body;

[0064] ζ3 is a non-dimensional damping coefficient of an equivalent longitudinal impact liquid in the B type connected tank body;

[0065] ζ4 is a non-dimensional damping coefficient of an equivalent longitudinal impact liquid in the B type divided tank body.

[0066] The beneficial effect of the further scheme is that the calculation method of the non-dimensional damping coefficient c of the equivalent longitudinal impact liquid under the condition of different tank bodies and different liquid filling ratios is realized.

[0067] According to another aspect of the present application, a liquid tank truck braking performance analysis method is provided, comprising the analysis method of the longitudinal impact performance of the liquid in the tank body.

[0068] Compared with the prior art, the present application has the following beneficial effects: through the equivalent mechanical model of the longitudinal impact of the liquid in the tank body, the change curve of the displacement x1 of the equivalent longitudinal impact liquid relative to the tank body with time and the calculation of the mass m str of the equivalent longitudinal impact liquid after the tank body is braked are realized.

[0069] Through the acquisition of the system parameter information of different types of tank bodies and the variable parameter information of the required detected tank body, the simulation detection of different types of tank bodies under different liquid filling ratios can be performed.

[0070] Through the calculation of the change curve of the displacement x1 of the equivalent longitudinal impact liquid relative to the tank body with time and the mass m str , m sta of the equivalent longitudinal impact liquid, the influence of the impact of the liquid along the longitudinal axis of the tank body on the braking effect of the tank body under the action of the braking force can be effectively reflected.

[0071] Thus, the influence of the longitudinal impact of the liquid in different types of tank bodies on the braking of the liquid tank truck is calculated after the liquid tank truck is braked; and the longitudinal displacement x2 of the liquid tank truck from the initial position at the braking moment is calculated through the influence of the longitudinal impact of the liquid in different types of tank bodies on the braking of the liquid tank truck in combination with the longitudinal dynamics equation of the liquid tank truck.

[0072] Further, the liquid tank truck braking performance analysis method further comprises obtaining the longitudinal displacement x2 of the liquid tank truck from the initial position at the braking moment to represent the braking performance of the liquid tank truck based on the whole vehicle longitudinal dynamics model of the liquid tank truck; and the whole vehicle longitudinal dynamics model of the liquid tank truck is constructed through the following steps: the longitudinal dynamics equation of the liquid tank truck is constructed with the displacement x1 of the equivalent longitudinal impact liquid relative to the tank body and the longitudinal displacement x2 of the liquid tank truck from the initial position at the braking moment as independent variables.

[0073] The longitudinal dynamics equation of the liquid tank truck is combined with an equivalent static liquid mass m sta , an equivalent longitudinal impact liquid mass m str ; the longitudinal displacement x2 of the liquid tank truck from the initial position at the braking time after braking is calculated;

[0074] The longitudinal dynamics equation of the liquid tank truck includes:

[0075]

[0076]

[0077] m is the total mass of the liquid tank truck;

[0078] n is the number of sub-chambers of the tank body;

[0079] x2 is the longitudinal displacement of the vehicle from the initial position at the braking time after braking;

[0080] F b is the braking force of the vehicle brake;

[0081] F f is the frictional resistance between the tire and the ground;

[0082]

[0083] F f ≤μ(m+m c )﹒g;

[0084] μ is the adhesion coefficient between the tire and the ground;

[0085] When n = 1, the tank body is a connected tank body, and when n > 1, the tank body is a divided tank body. n is the number of sub-chambers of the tank body;

[0086] The beneficial effects of the above further scheme are that the longitudinal dynamics equation of the liquid tank truck includes:

[0087] The longitudinal displacement x2 of the liquid tank truck from the initial position at the braking time after braking is achieved;

[0088] The equivalent mechanical model of the longitudinal impact of the liquid in the tank body solves the problem of the significant difference in the longitudinal impact force of the liquid in the tank body due to the setting of the transverse fender in the tank body for both connected and divided tank bodies;

[0089] The longitudinal dynamics equation of the liquid tank truck achieves the problem of the significant difference in the longitudinal impact force of the liquid in the tank body due to the different number of sub-chambers set in the tank body;

[0090] Therefore, the longitudinal displacement x2 of the liquid tank truck from the initial position at the time of braking can be simulated and calculated by the liquid tank truck braking performance analysis method. BRIEF DESCRIPTION OF DRAWINGS

[0091] Figure 1 is a comparison chart of the liquid longitudinal impact force in the B-type connected tank with a liquid filling ratio of 0.3 by CFD simulation and the MSD calculation result of the liquid longitudinal impact equivalent mechanical model of the application;

[0092] Figure 2 is a comparison chart of the liquid longitudinal impact force in the B-type connected tank with a liquid filling ratio of 0.5 by CFD simulation and the MSD calculation result of the liquid longitudinal impact equivalent mechanical model of the application;

[0093] Figure 3 is a braking deceleration-time curve of an ordinary truck, a liquid tank truck loaded with a B-type connected tank and a liquid tank truck loaded with a B-type separated tank under the same braking condition when the tank liquid filling ratio is 0.2 and the initial braking speed is 15 m / s;

[0094] Figure 4 is a braking speed-time curve of an ordinary truck, a liquid tank truck loaded with a B-type connected tank and a liquid tank truck loaded with a B-type separated tank under the same braking condition when the tank liquid filling ratio is 0.2 and the initial braking speed is 15 m / s;

[0095] Figure 5 is a braking distance-time curve of an ordinary truck, a liquid tank truck loaded with a B-type connected tank and a liquid tank truck loaded with a B-type separated tank under the same braking condition when the tank liquid filling ratio is 0.2 and the initial braking speed is 15 m / s. DETAILED DESCRIPTION

[0096] In order to better understand the technical solutions of the application, the application will be further described below in combination with specific embodiments.

[0097] Embodiment 1

[0098] According to an aspect of the embodiment, a method for analyzing liquid longitudinal impact performance in a tank is provided, characterized in that the method comprises the following steps: constructing a liquid longitudinal impact equivalent mechanical model in the tank by using a spring mass model; classifying the tank; obtaining variable parameter information of the required tank to be detected; and obtaining system parameter information of different types of tanks.

[0099] According to the variable parameter information, the system parameter information and the liquid longitudinal impact equivalent mechanical model in the tank, a displacement-time curve of an equivalent longitudinal impact liquid relative to the tank x1 and an equivalent longitudinal impact liquid mass m str are calculated.

[0100] The equivalent longitudinal impact liquid is a liquid whose centroid position is displaced along the direction of motion of the tank;

[0101] The displacement x1 of the equivalent longitudinal impact liquid relative to the tank is the displacement of the centroid of the equivalent longitudinal impact liquid along the direction of motion of the tank;

[0102] During the motion or braking of the tank, the mass m str of the equivalent longitudinal impact liquid does not change with time; the mass of the equivalent longitudinal impact liquid is only related to the shape of the tank, the arrangement of the fender, and the liquid filling ratio in the tank;

[0103] The variable parameter information is a parameter directly obtained during the motion or braking of the tank; the system parameter information is a parameter information calculated based on the shape of the tank, the arrangement of the fender, and the variable parameter information. The tank type includes a connected tank and a separated tank; the connected tank includes an A-type connected tank and a B-type connected tank; the separated tank includes an A-type separated tank and a B-type separated tank;

[0104] The connected tank is a tank without a fender intersecting the direction of motion or force of the tank, so that the liquid sloshing is not affected by the fender at all, and the liquid longitudinal sloshing is not inhibited; the liquid longitudinal sloshing direction is parallel to the direction of motion of the tank;

[0105] The separated tank is a tank in which a transverse fender without apertures such as manholes and flow holes is arranged according to the requirement of the number of transverse fenders in the national standard, so as to separate the tank into multiple completely disconnected cabins; the liquid in different cabins of the separated tank does not flow at all, and the liquid sloshing is most inhibited;

[0106] The A-type connected tank is a connected tank with an aspect ratio of 1.5;

[0107] The B-type connected tank is a connected tank with an aspect ratio of 2;

[0108] The A-type separated tank is a separated tank with an aspect ratio of 1.5;

[0109] The B-type separated tank is a separated tank with an aspect ratio of 2;

[0110] Preferably, the cross section of the tank is an ellipse, and the aspect ratio is the ratio of the major axis and the minor axis of the cross section of the tank;

[0111] The variable parameter information includes m c , π, and a; the m cThe liquid quality in the tank is stored in the tank; the π is the liquid filling ratio in the tank; the a is the longitudinal acceleration obtained by the external excitation of the tank; the liquid filling ratio is defined as the ratio of the liquid level height to the tank height; the liquid filling ratio changes from 0.1 to 0.9 with a step length of 0.1 to cover most of the tank filling levels; the longitudinal acceleration obtained by the external excitation of the tank changes from 0.1g to 1.0g with a step length of 0.1g;

[0112] The system parameter information includes k and c; the k is the equivalent longitudinal impact liquid spring stiffness; the c is the equivalent longitudinal impact liquid dimensionless damping coefficient;

[0113] The liquid longitudinal impact equivalent mechanical model includes a spring mass model dynamics equation and an equivalent longitudinal impact liquid quality and tank stored liquid quality ratio calculation formula;

[0114] The dynamics equation of the spring mass model is:

[0115]

[0116] The The second derivative of the equivalent longitudinal impact liquid displacement x1 relative to the tank is:

[0117] The The first derivative of the equivalent longitudinal impact liquid displacement x1 relative to the tank is:

[0118] m sta The equivalent static liquid mass is:

[0119] The equivalent longitudinal impact liquid quality and tank stored liquid quality ratio calculation formula includes:

[0120] (m str / m c )1=-0.6319π 3 +0.4973π 2 +0.1596π+0.089;

[0121] (m str / m c )2=2.1770π 3 -7.0441π 2 +4.9615π-0.1812;

[0122] (m str / m c )3=-2.9710π 3 +3.6615π 2 -0.9185π+0.1722;

[0123] (mstr / m c )4=1.2005π 3 -5.6508π 2 +4.4139π-0.1068;

[0124] The (m str / m c )1 is a ratio of an equivalent longitudinal impact liquid mass in the A-type connected tank body to a storage liquid mass in the tank body;

[0125] The (m str / m c )2 is a ratio of an equivalent longitudinal impact liquid mass in the A-type separated tank body to a storage liquid mass in the tank body;

[0126] The (m str / m c )3 is a ratio of an equivalent longitudinal impact liquid mass in the B-type connected tank body to a storage liquid mass in the tank body;

[0127] The (m str / m c )4 is a ratio of an equivalent longitudinal impact liquid mass in the B-type separated tank body to a storage liquid mass in the tank body.

[0128] The calculation formula of the k is k=ω 2 ·m c ; the ω is a longitudinal free oscillation angular frequency of the equivalent longitudinal impact liquid.

[0129] The ω includes ω1, ω2, ω3 and ω4;

[0130] The ω1 is a free oscillation angular frequency of the equivalent longitudinal impact liquid when the tank body is the A-type connected tank body;

[0131] The ω2 is a free oscillation angular frequency of the equivalent longitudinal impact liquid when the tank body is the A-type separated tank body;

[0132] The ω3 is a free oscillation angular frequency of the equivalent longitudinal impact liquid when the tank body is the B-type connected tank body;

[0133] The ω4 is a free oscillation angular frequency of the equivalent longitudinal impact liquid when the tank body is the B-type separated tank body;

[0134] ω1=-0.0641π 2 -0.5239π+3.6147;

[0135] ω2=-0.0335π 2 -0.0927π+4.4521;

[0136] ω3=-0.0945π2 -0.7993π+4.2041;

[0137] ω4 = -0.0550π 2 -0.3940π+5.3758.

[0138] the formula of c is:

[0139] ζ includes ζ1, ζ2, ζ3, ζ4;

[0140] ζ1 = -0.0114π 2 +0.0046π+0.2337;

[0141] ζ2 = 0.0338π 2 -0.2783π+0.5596;

[0142] ζ3 = 0.0289π 2 -0.1759π+0.6747;

[0143] ζ4 = -0.0361π 2 -0.2495π+0.5454;

[0144] The ζ1 is an equivalent longitudinal impact liquid dimensionless damping coefficient of the tank body as an A type connected tank body.

[0145] The ζ2 is an equivalent longitudinal impact liquid dimensionless damping coefficient of the tank body as an A type separated tank body.

[0146] The ζ3 is an equivalent longitudinal impact liquid dimensionless damping coefficient of the tank body as a B type connected tank body.

[0147] The ζ4 is an equivalent longitudinal impact liquid dimensionless damping coefficient of the tank body as a B type separated tank body.

[0148] According to another aspect of the embodiment, a liquid tank truck braking performance analysis method is provided, including the analysis method of the longitudinal impact performance of the liquid in the tank body.

[0149] The liquid tank truck braking performance analysis method further includes obtaining the longitudinal displacement x2 of the liquid tank truck from the initial position at the braking time after braking to represent the braking performance of the liquid tank truck based on a whole vehicle longitudinal dynamics model of the liquid tank truck.

[0150] The whole vehicle longitudinal dynamics model of the liquid tank truck is constructed by the following steps: constructing a longitudinal dynamics equation of the liquid tank truck with the displacement x1 of the equivalent longitudinal impact liquid relative to the tank body and the longitudinal displacement x2 of the liquid tank truck from the initial position at the braking time after braking as independent variables.

[0151] The liquid tank truck longitudinal dynamics equation is used to calculate the longitudinal displacement x2 of the liquid tank truck from the initial position at the braking time after braking;

[0152] The liquid tank truck longitudinal dynamics equation includes:

[0153]

[0154]

[0155] The m is the total mass of the liquid tank truck;

[0156] The n is the number of sub-warehouses of the tank body;

[0157] The x2 is the longitudinal displacement of the vehicle from the initial position at the braking time;

[0158] The F b is the braking force of the vehicle brake;

[0159] The F f is the frictional resistance between the tire and the ground;

[0160]

[0161] F f ≤μ(m+m c )﹒g;

[0162] The μ is the adhesion coefficient between the tire and the ground.

[0163] Through Figure 1 and Figure 2 it is shown that the liquid longitudinal impact force in the tank body calculated by the CFD simulation method is basically consistent with the calculation result of the liquid longitudinal impact equivalent mechanical model of the application, so that the liquid longitudinal impact force in the tank body can be effectively calculated by the liquid longitudinal impact equivalent mechanical model in the tank body;

[0164] Through Figures 3-5 it is shown that the braking deceleration-time curve, the braking speed-time curve and the braking distance-time curve of the ordinary cargo vehicle and the liquid tank truck loaded with different types of tank bodies under the same braking condition can be effectively calculated by the liquid longitudinal impact equivalent mechanical model in the tank body; at the same time, it is shown that the braking distance of the liquid tank truck is smaller than the braking deceleration of the ordinary cargo vehicle, and the braking distance is larger; compared with the continuous tank body, the liquid longitudinal impact strength in the tank body is low, the braking deceleration is large, and the braking distance is small.

[0165] The above description is only the preferred embodiment of the present application and the explanation of the technical principles. It should be understood by those skilled in the art that the scope of the application involved in the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by the combinations of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are equivalent to the features disclosed in the present application (but not limited to) with similar functions.

Claims

1. A method for analyzing the longitudinal impact performance of liquids inside a tank, characterized in that, Includes the following steps: An equivalent mechanical model of longitudinal impact of liquid inside the tank is constructed based on the spring mass model. Classify the tanks; Obtain variable parameter information and system parameter information for different types of tanks; Based on the variable parameter information and system parameter information of different types of tanks, combined with the equivalent mechanical model of longitudinal impact of liquid in the tank, the displacement x1 of the equivalent longitudinal impact liquid relative to the tank relative to the tank and the equivalent longitudinal impact liquid mass m are calculated as follows: str To characterize the longitudinal impact performance of the liquid inside the tank; The variable parameter information includes m c , π, a; Where, m c π represents the mass of liquid stored in the tank; π represents the liquid filling ratio in the tank; and a represents the longitudinal acceleration of the tank under external excitation. The system parameter information includes k and c; Where k is the spring stiffness of the equivalent longitudinally impacting liquid; c is the dimensionless damping coefficient of the equivalent longitudinally impacting liquid. The equivalent mechanical model of longitudinal liquid impact includes the dynamic equation of the spring mass model and the calculation formula for the ratio of the equivalent longitudinal impact liquid mass to the liquid mass stored in the tank. The dynamic equation of the spring-mass model is: in, The second derivative of the equivalent longitudinal impact liquid displacement x1 relative to the tank; The first derivative of the equivalent longitudinal impact liquid displacement x1 relative to the tank; m sta The equivalent static liquid mass; The formula for calculating the ratio of the equivalent longitudinal impact liquid mass to the liquid mass stored in the tank includes: ((m str / mc)1= -0.6319π 3 +0.4973π 2 +0.1596π+0.089; (m str / mc)2=2.1770π 3 -7.0441π 2 +4.9615π-0.1812; (m str / mc)3= -2.9710π 3 +3.6615π 2 -0.9185π+0.1722; (m str / mc)4=1.2005π 3 -5.6508π 2 +4.4139π-0.1068; Among them, (m str / mc)1 is the ratio of the equivalent longitudinal impact liquid mass in the Type A connected tank to the liquid mass stored in the tank; (m str / mc)2 is the ratio of the equivalent longitudinal impact liquid mass in the Type A partitioned tank to the mass of the liquid stored in the tank; (m str / mc)3 is the ratio of the equivalent longitudinal impact liquid mass in the type B interconnected tank to the liquid mass stored in the tank. (m str / mc)4 is the ratio of the equivalent longitudinal impact liquid mass in the Type B partitioned tank to the liquid mass stored in the tank.

2. The method for analyzing the longitudinal impact performance of liquid in a tank according to claim 1, characterized in that, The tank types include interconnected tanks and partitioned tanks; The connected tank includes type A connected tank and type B connected tank; The partitioned tanks include Type A partitioned tanks and Type B partitioned tanks.

3. The method for analyzing the longitudinal impact performance of liquid in a tank according to claim 1, characterized in that... k is calculated using the following formula: k = ω 2 mc; Where ω is the free angular frequency of the equivalent longitudinally impacting liquid.

4. The method for analyzing the longitudinal impact performance of liquid in a tank according to claim 1, characterized in that, ω includes ω1, ω2, ω3, and ω4; Wherein, ω1 is the free oscillation angular frequency of the equivalent longitudinal impact liquid in the type A connected tank; ω2 is the free angular frequency of the equivalent longitudinal impact liquid in the type A partitioned tank; ω3 is the free angular frequency of the equivalent longitudinal impact liquid in the type B interconnected tank; ω4 is the free angular frequency of the equivalent longitudinal impact liquid in the type B partitioned tank; ω1=-0.0641π 2 -0.5239π+3.6147; ω2=-0.0335π 2 -0.0927π+4.4521; ω3=-0.0945π 2 -0.7993π+4.2041; ω4=-0.0550π 2 -0.3940π + 5.3758.

5. The method for analyzing the longitudinal impact performance of liquid in a tank according to claim 1, characterized in that, The value of c is calculated using the following formula: ; Among them, ζ includes ζ1, ζ2, ζ3, and ζ4; ζ1=-0.0114π 2 +0.0046π +0.2337; ζ2=0.0338π 2 -0.2783π+0.5596; ζ3=0.0289π 2 -0.1759π+0.6747; ζ4=-0.0361π 2 -0.2495π+0.5454; ζ1 is the dimensionless damping coefficient of the equivalent longitudinal impact fluid in the type A connected tank. ζ2 is the dimensionless damping coefficient of the equivalent longitudinal impact fluid in the type A partitioned tank. ζ3 is the dimensionless damping coefficient of the equivalent longitudinal impact fluid in the type B interconnected tank. ζ4 is the dimensionless damping coefficient of the equivalent longitudinal impact fluid in the type B partitioned tank.

6. A method for analyzing the braking performance of a liquid tanker truck, characterized in that, The method for analyzing the longitudinal impact performance of liquids inside a tank, as described in any one of claims 1-5.

7. The method for analyzing the braking performance of a liquid tanker truck according to claim 6, further characterized by including obtaining the longitudinal displacement x2 of the liquid tanker truck after braking from the initial position at the braking moment based on the longitudinal dynamic model of the liquid tanker truck to characterize the braking performance of the liquid tanker truck; in, The longitudinal dynamics model of the liquid tanker truck is constructed through the following steps: The longitudinal dynamic equation of the tank truck is constructed with the displacement x1 of the equivalent longitudinal impact liquid relative to the tank body and the longitudinal displacement x2 of the tank truck from the initial position at the braking moment after braking as independent variables. The longitudinal dynamic equation of the liquid tanker truck is combined with the equivalent static liquid mass m sta The equivalent longitudinal impact fluid mass m str Calculate the longitudinal displacement x2 of the tanker truck from its initial position at the moment of braking after braking; The longitudinal dynamic equations of the tanker truck include: m represents the curb weight of the tanker truck; n is the number of compartments in the tank; x2 is the longitudinal displacement of the vehicle from its initial position at the moment of braking; F b To provide braking force to the vehicle's brakes; F f This refers to the frictional resistance between the tire and the ground. F f ≤μ(m+mc)﹒g; μ is the coefficient of adhesion between the tire and the ground.

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