CN105956264A - Temperature field simulated analysis method applied to multi-disk dry brake under comprehensive action of multiple physical fields - Google Patents

Abstract

The invention discloses a temperature field simulated analysis method applied to a multi-disk dry brake under the comprehensive action of multiple physical fields. Firstly, a three-dimensional model of the brake is established by starting from the mechanism and movement principle of the multi-disk dry brake. Then according to the complementarity between a fluid field and the brake structure, a rough fluid model is established and then modified and cut, and thus a final fluid model is acquired. Then fluid region and solid region boundary conditions are computed, a heat-flux coupling analysis is performed, and a temperature distribution rule of the whole brake is acquired. At last, a thermo-solid coupling analysis is performed, and a temperature field-to-brake structure deformation parameter is acquired. The temperature field simulated analysis method can achieve the temperature field simulated analysis of the multi-disk dry brake under the comprehensive action of multiple physical fields, is more accurate and reliable than the traditional single temperature field analysis, adopts zonal solving and boundary coupling methods, thus optimizing the information flow among the physical fields, and thus, the simulation is simpler, the operation is convenient and the consumed time is greatly shortened.

Description

A kind of Temperature Field Simulation under polydisc dry brake multiple physical field comprehensive function analyzes method

Technical field

The invention belongs to endless-track vehicle transmission field friction pairs of brake temperature simulation analysis technical field, particularly to a kind of polydisc Temperature Field Simulation under the multiple physical field comprehensive function of dry brake analyzes method.

Background technology

High-energy-density friction driven system is the key of high performance power transmission, and it is noteworthy characterized by rotating speed high-power, high, due to it Excellent wearability and higher thermal capacitance are widely used in the transmission field of endless-track vehicle.

Engineering truck polydisc dry brake mechanism includes pellet pressing mechanism, frictional damping mechanism and supporting construction.As it is shown on figure 3, Pellet pressing mechanism is by selecting rotating disk 1, pellet 2 and mobile dish 3 to form, and frictional damping mechanism is by upper frictional disk 4, antithesis dish 5 Forming with lower frictional disk 6, supporting construction has shell 7, spring upper cover 8 and base 9, as shown in Figure 2.

At present, the method for the research of brake multiple physical field is the most immature.Previously due to software function and the limit of computing power System, research worker is all only limitted to the single or simulation study of two physical fields or only single frictional disk has been carried out simulation study, And have ignored the globality of brake；Brake is as part more than, the mechanism that does more physical exercises, its conduction of heat, heat convection etc. Affected by many factors, the aspect therefore should analyzed from whole brake system, set up the contact between each parts, To guarantee accuracy and the precision of initial condition and boundary condition.

Summary of the invention

The technical problem to be solved in the present invention is: be the drawbacks described above in order to overcome prior art, it is proposed that a kind of dry for polydisc Study on Temperature Field method under formula brake multiple physical field comprehensive function, utilizes the method can arrange for fluid domain and solid domain Individually solver decomposed domain, then uses the form of border coupling, makes simulation result more rationally more accurate.

The technical solution used in the present invention is: a kind of Temperature Field Simulation under polydisc dry brake multiple physical field comprehensive function Analysis method, as shown in Figure 1, it is characterised in that realize step as follows:

Step one, the mechanical feature analyzing polydisc dry brake and motion principle, it is thus achieved that the physical dimension of each parts of brake；

Step 2, set up brake finite element according to the mechanical feature of brake and its physical dimension analyzing acquisition in step one Analyze model；

Step 3, according to complementary between brake and its fluid model, set up fluid blank, then deduct wheel hub etc., generate Fluid model, as shown in Figure 3；Then it is assembled into coupling model with the brake model in step 2；

Step 4, the thinking of employing differential, be divided into countless fritter by frictional contact surface, uses frictional force to do manual work and changes into heat Method, calculate the quantity of heat production of friction pair under given working condition；

Concrete Computing Principle is: the frictional contact surface of brake pad and brake disc is divided into many fritters, and the area of each fritter is designated as dA.Brake pad is designated as p (t) to the normal direction pressure of brake disc, then the frictional force occurred on dA area is:

DF=μ P (t) dA

The distance that then frictional force dF acted within the dt time is:

DS=ω (t) r dt

Assume that on dA area, frictional force dF work done within the dt time of effect is completely converted into heat, then producing heat is:

DQ=dF dS=μ P (t) dA ω (t) r dt

Therefore, in braking procedure, the heat flow density on brake friction dish frictional layer is:

Q (r, t)=dQ/ (dA dt)=μ P (t) ω (t) r

In formula, the μ coefficient of sliding friction, P (t) frictional disk pressure, ω (t) brake disc rotating speed.

Step 5, employing hot-fluid distribution model, calculate the hot-fluid distribution between antithesis dish and frictional disk；Specific formula for calculation and rubbing The material parameter of wiping dish and antithesis dish is as follows:

Assume that the heat flow density of frictional disk and antithesis dish is respectively q_{N (r, t)}, q_{M (r, t)}, according to the material properties of friction element in table 1, The partition coefficient K of heat flow density can be tried to achieve_q, as follows:

$K_q=\frac{q_{m(r,t)}}{q_{n(r,t)}}=\left(\frac{{\mathrm{\λ}}_m{C}_m{\mathrm{\ρ}}_m}{{\mathrm{\λ}}_n{C}_n{\mathrm{\ρ}}_n}\right)$

In formula: λ_mFor the hot coefficient of antithesis dish, C_mFor antithesis dish specific heat, ρ_mFor antithesis dish density；λ_nFor frictional disk heat conductivity, C_nFor frictional disk specific heat, ρ_nFor frictional disk density.

Known:

Q (r, t)=q_m(r,t)+q_n(r,t)

Above formula simultaneous can obtain:

$q_{n(r,t)}=\frac{q_{(r,t)}}{1+K_q}$

$q_{m(r,t)}=\frac{K_q\·q_{(r,t)}}{1+K_q}$

Thermal, Structure and Fluent module in step 6, employing ANSYS Workbench, builds coupling letter Breath transmission platform, as shown in Figure 4；

Step 7, the coupling model of step 3 is imported Fluent module, FLuent applies convection transfer rate and wall Initial temperatures etc., apply the boundary condition calculated in step 4 and step 5 in Thermal, carry out stress and strain model, and three Individual module arranges the result needing to obtain；

Step 8, on the main interface of Workbench, click Update by right key, start calculate.

Present invention advantage compared with prior art is:

Compared to traditional multiple physical field coupled modes, the present invention is directed to the temperature field under multiple physical field comprehensive function and use subregion to ask Solve, border couples and the mode of cell translation, simplifies operation easier, shortens simulation time, makes simulation result more reasonable, The regularity of distribution for research brake temperature field proposes a set of practicable simulation flow.

Accompanying drawing explanation

Fig. 1 is the inventive method flowchart；

Fig. 2 is polydisc dry brake structure diagram in the present invention；

Fig. 3 is hollow cold fluid model of the present invention；

Fig. 4 is that in the present invention, coupling information flows to.

Detailed description of the invention

In order to understand the technical characterstic of explanation this programme, below by a specific embodiment, and combine its accompanying drawing to we Case is illustrated.

Step one, the working condition determined under brake operation state (predominantly load and rotating speed)；Frictional disk, antithesis dish With physical dimension and the pellet pressure structure feature of pellet pressure structure, provide the parameter support of necessity for setting up of phantom.

Step 2, in Pro/E, set up the threedimensional model of each part of brake, and in assembling module, assemble molding, according to Between brake and its fluid model, complementarity, sets up fluid blank, then deducts wheel hub etc., generates fluid model, such as Fig. 3 Shown in；Then it is assembled into coupling model with the brake model in step 2.

Step 3, the thinking of employing differential, be divided into countless fritter by frictional contact surface, uses frictional force to do manual work and changes into heat Method, calculate the quantity of heat production of friction pair under given working condition；

Concrete Computing Principle is: the frictional contact surface of brake pad and brake disc is divided into many fritters, and the area of each fritter is designated as dA.Brake pad is designated as p (t) to the normal direction pressure of brake disc, then the frictional force occurred on dA area is:

DF=μ P (t) dA

The distance that then frictional force dF acted within the dt time is:

DS=ω (t) r dt

Assume that on dA area, frictional force dF work done within the dt time of effect is completely converted into heat, then producing heat is:

DQ=dF dS=μ P (t) dA ω (t) r dt

Therefore, in braking procedure, the heat flow density on brake friction dish frictional layer is:

Q (r, t)=dQ/ (dA dt)=μ P (t) ω (t) r

In formula, the μ coefficient of sliding friction, P (t) frictional disk pressure, ω (t) brake disc rotating speed.

Step 5, employing hot-fluid distribution model, calculate the hot-fluid distribution between antithesis dish and frictional disk；Specific formula for calculation and rubbing The material parameter of wiping dish and antithesis dish is as follows:

The material properties of table 1 friction element

Assume that the heat flow density of frictional disk and antithesis dish is respectively q_{N (r, t)}, q_{M (r, t)}, according to the material properties of friction element in table 1, The partition coefficient K of heat flow density can be tried to achieve_q, as follows:

$K_q=\frac{q_{m(r,t)}}{q_{n(r,t)}}=\left(\frac{{\mathrm{\λ}}_m{C}_m{\mathrm{\ρ}}_m}{{\mathrm{\λ}}_n{C}_n{\mathrm{\ρ}}_n}\right)=2.7$

In formula: λ_mFor the hot coefficient of antithesis dish, C_mFor antithesis dish specific heat, ρ_mFor antithesis dish density；λ_nFor frictional disk heat conductivity, C_nFor frictional disk specific heat, ρ_nFor frictional disk density.

Known:

Q (r, t)=q_m(r,t)+q_n(r,t)

Above formula simultaneous can obtain:

$q_{n(r,t)}=\frac{q_{(r,t)}}{1+K_q}=0.27q_{(r,t)}$

$q_{m(r,t)}=\frac{K_q\·q_{(r,t)}}{1+K_q}=0.73q_{(r,t)}$

Thermal, Structure and Fluent module in step 6, employing ANSYS Workbench, builds coupling letter Breath transmission platform, as shown in Figure 4；

Step 7, the coupling model of step 3 is imported Fluent module, FLuent applies convection transfer rate and wall Initial temperatures etc., apply the boundary condition calculated in step 4 and step 5 in Thermal, carry out stress and strain model, and three Individual module arranges the result needing to obtain；

Step 8, on the main interface of Workbench, click Update by right key, start calculate.

The present invention is not limited in above-mentioned detailed description of the invention, and those of ordinary skill in the art make in the essential scope of the present invention Change, retrofit, add or replace, also should belong to protection scope of the present invention.

Claims (1)

1. the Temperature Field Simulation under polydisc dry brake multiple physical field comprehensive function analyzes method, it is characterised in that Realize step as follows:

Step one, the mechanical feature analyzing polydisc dry brake and motion principle, it is thus achieved that the physical dimension of each parts of brake；

Step 2, set up brake finite element according to the mechanical feature of brake and its physical dimension analyzing acquisition in step one Analyze model；

Step 3, according to complementary between brake and its fluid model, set up fluid blank, then deduct wheel hub, generate stream Body Model；Then it is assembled into coupling model with the brake model in step 2；

Step 4, the thinking of employing differential, be divided into countless fritter by frictional contact surface, uses frictional force to do manual work and changes into heat Method, calculate the quantity of heat production of friction pair under given working condition；

Concrete Computing Principle is: the frictional contact surface of brake pad and brake disc is divided into many fritters, and the area of each fritter is designated as DA, is designated as p (t) brake pad to the normal direction pressure of brake disc, then the frictional force occurred on dA area is:

DF=μ P (t) dA

The distance that then frictional force dF acted within the dt time is:

DS=ω (t) r dt

Assume that on dA area, frictional force dF work done within the dt time of effect is completely converted into heat, then producing heat is:

DQ=dF dS=μ P (t) dA ω (t) r dt

Therefore, in braking procedure, the heat flow density on brake friction dish frictional layer is:

Q (r, t)=dQ/ (dA dt)=μ P (t) ω (t) r

In formula, the μ coefficient of sliding friction, P (t) frictional disk pressure, ω (t) brake disc rotating speed；

Step 5, employing hot-fluid distribution model, calculate the hot-fluid distribution between antithesis dish and frictional disk；Specific formula for calculation and rubbing The material parameter of wiping dish and antithesis dish is as follows:

Assume that the heat flow density of frictional disk and antithesis dish is respectively q_n(r,t), q_m(r,t), the partition coefficient K of heat flow density can be tried to achieve_q, As follows:

$K_q=\frac{q_{m(r,t)}}{q_{n(r,t)}}=\left(\frac{{\mathrm{\λ}}_m{C}_m{\mathrm{\ρ}}_m}{{\mathrm{\λ}}_n{C}_n{\mathrm{\ρ}}_n}\right)$

In formula: λ_mFor the hot coefficient of antithesis dish, C_mFor antithesis dish specific heat, ρ_mFor antithesis dish density；λ_nFor frictional disk heat conductivity, C_nFor frictional disk specific heat, ρ_nFor frictional disk density；

Known:

Q (r, t)=q_m(r,t)+q_n(r,t)

Above formula simultaneous can obtain:

$q_{n(r,t)}=\frac{q_{(r,t)}}{1+K_q}$

$q_{m(r,t)}=\frac{K_q\·q_{(r,t)}}{1+K_q}$

Temperature analysis module (Thermal) in step 6, employing finite element analysis software (ANSYS Workbench), knot Structure degree analyzes module (Structure) and fluid analysis module (Fluent), builds coupling information transmission platform；

Step 7, the coupling model of step 3 is imported fluid analysis module (Fluent), in FLuent (fluid analysis module) Middle applying convection transfer rate and wall initial temperature etc., apply step 4 and step in temperature analysis module (Thermal) The boundary condition calculated in five, carries out stress and strain model, and arranges the result needing to obtain in three modules；

Step 8, on finite element analysis software (ANSYS Workbench) main interface, click " renewal " (Update) by right key, Start to calculate.