CN103559361A - Intensity optimization method and stress analysis method for component - Google Patents

Abstract

The invention discloses a stress analysis method for a component. The method comprises the following steps: performing finite element analysis on the component so as to obtain linear stress distribution and side line loads at two ends of a unit; inserting a first node and a second node at the inner part and the outer part of the region of stress concentration respectively, and dividing the unit into three subunits; according to the principle that force and force moment of the unit are equal to resultant force and resultant moment of the three subunits respectively, obtaining the respective side line load of each of the three subunits; using the multi-section linear stress distribution of the three subunits to replace the linear stress distribution of the unit, so that the stress analysis value of the unit is obtained. According to the invention, piecewise linear load distribution is adopted to fit the linear load distribution of the original unit, and the obtained analysis result of the unit with larger size is amended to close to the practical situation, so that the accuracy of component stress analysis is improved obviously; meanwhile, the work efficiency is improved. On the basis of the stress analysis method for the component, the invention further provides an intensity optimization method for the component.

Description

A kind of optimization method of component strength and stress analysis method thereof

Technical field

The present invention relates to the structure member design of the industries such as boats and ships, ocean platform, aviation and vehicle, be specifically related to optimization method and the stress analysis method thereof of component strength.

Background technology

Finite element analysis (FEA, Finite Element Analysis) be a kind of modern computing method, it adopts the method for mathematical approach to simulate actual physical system (how much and load working condition), utilize simple and interactional element (being unit), with the unknown quantity of limited quantity, remove to approach the real system of unlimited unknown quantity.Utilize finite element analysis to carry out detailed mechanical analysis to structural member (member), can obtain member and under real use state, be subject to as far as possible really force information, thereby can to the variety of issue that may occur, carry out safety evaluation in the design phase, and carry out corresponding design parameter modification.According to interrelated data, record, the structural design defect of a new product has more than 60% and can eliminate in the design phase, and therefore, the such analysis means of finite element analysis is performed meritorious deeds never to be obliterated.At present, finite element analysis has been widely used in the field of engineering technology of different subjects, to guarantee the working strength of member.

When carrying out finite element analysis, for the larger member of physical dimension, conventionally can adopt larger size of mesh opening (unit size) to carry out modeling, to improve the efficiency of analytical calculation.But, for the region greatly of the stress gradient variation on member, (rigidity of structure that is generally member changes region greatly, also be region of stress concentration), because its stress distribution generally shows as nonlinear Distribution, therefore, adopt larger unit size to carry out finite element analysis, can not describe well the nonlinear Distribution situation of the stress of this unit, specifically refer to following example.

Member shown in Fig. 1 is a kind of tee T welding joint, wherein, and the long 3000mm of base plate 11, wide 1000mm; The long 1000mm of riser 12, high 500mmm; The thickness of slab t of base plate 11 and riser 12 is 5mm; The base of riser 12 is welded on the right-hand member end face of base plate 11, and the height of weld seam 13 is 5mm.The right-hand member of this tee T welding joint is fixed, and left end loads, and adopts plate shell unit to carry out finite element analysis.When the length of setup unit is 100 * t=500mm, riser 12 is divided two unit (A1, A2) for as shown in Figure 2, and the linear load in the stress distribution on unit A1 as shown in Fig. 4 cathetus Z1 distributes.

Yet, in said structure, weld seam 13 positions of base plate 11 and riser 12 necessarily have obvious stress and concentrate, that is to say, in fact the stress distribution in this region should show as obvious nonlinear Distribution, obviously, in Fig. 4 there is a certain distance with actual conditions in the distribution of the linear load shown in Z1.In order to obtain relatively accurate result, while carrying out finite element analysis, while carrying out stress evaluation for thin portion structure, (particularly region of stress concentration), needs refinement Local grid conventionally.For the structure shown in Fig. 1, when the length of setup unit is 12.5 * t=62.5mm as shown in Figure 3, unit A1 is divided for 8 unit, by having obtained the curve shown in Z2 in Fig. 4 after finite element analysis, curve Z2 just can show the non-linear stress distribution situation of the root of weld well.

As can be seen here, in the finite element analysis process to member, the result impact that unit size counter stress is analyzed is larger, especially more obvious at region of stress concentration.Although can obtain by the mode of tessellated mesh relatively accurate result, this processing mode workload is large, solution efficiency is low, realizes more loaded down with trivial details.

In view of this, urgently for existing finite element method, be optimized design, to improve efficiency and the precision of member finite element analysis, further improve the strength reliability of member.

Summary of the invention

For above-mentioned defect, the technical matters that the present invention solves is to provide a kind of stress analysis method of member, with the precision of guaranteeing that component stress is analyzed, has effectively improved work efficiency simultaneously.On this basis, the present invention also provides the component strength optimization method of a kind of this stress analysis method of application.

The stress analysis method of member provided by the invention, comprises the following steps:

Member is carried out to finite element analysis, obtain the linear stress distribution of each unit and the sideline load at these two ends, unit;

In the region of stress concentration of the described unit of stress concentration portion position, inserting first node, at region of stress concentration, insert Section Point outward, is three subelements by this dividing elements;

According to the force and moment of described unit respectively with the making a concerted effort and principle that resultant moment equates of three described subelements, determine three described subelements sideline load separately;

The linear stress that the linear stress distribution of multistage forming with the sideline load of three described subelements substitutes this unit distributes, and obtains the stress analysis value of this unit.

Preferably, described first node and Section Point are divided into first, second, and third subelement successively by corresponding unit, wherein, the stress distribution of described the 3rd subelement is for all carrying, and sideline load ff3=(f1+f2)/2, wherein, f1 and f2 are the sideline load at these two ends, unit.

Preferably, sideline, two ends load ff1 and the ff2 of described the first subelement calculate by following formula:

$\begin{array}{c}\mathrm{ff}1=\frac{({l1}^2+l1\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">l</figure-callout>}2+L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;f1+\frac{({l1}^2+l1\&CenterDot;l2-L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">f</figure-callout>}2;\\ \mathrm{<figure-callout\; id="2"\; label="ff"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">ff</figure-callout>}2=\frac{[{(l1+l2)}^2-L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;f1+\frac{[{(l1+l2)}^2+L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">f</figure-callout>}2;\end{array}$

Wherein, the length that L is described unit, l1 is the distance between described first node and compare great sideline, this unit load, l2 is the distance between described Section Point and first node.

Preferably, the stress analysis value σ of described first node _s1stress analysis value σ with Section Point _s2by following formula, calculate respectively:

$\begin{array}{c}{\mathrm{\&sigma;}}_{s1}=\frac{\mathrm{ff}1}{t}+\frac{6\&CenterDot;\mathrm{mm}1}{{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">t</figure-callout>}}^2};\\ {\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">s</figure-callout>}2}=\frac{\mathrm{ff}2}{t}+\frac{6\&CenterDot;\mathrm{mm}2}{{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">t</figure-callout>}}^2};\end{array}$

Wherein, t is the member thickness that described unit is corresponding, and mm1, mm2 and mm3 are respectively the sideline load moment of first, second, and third subelement, and mm3=(m1+m2)/2;

$\begin{array}{c}\mathrm{mm}1=\frac{({l1}^2+l1\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">l</figure-callout>}2+L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;m1+\frac{({l1}^2+l1\&CenterDot;l2-L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">m</figure-callout>}2\\ \mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">mm</figure-callout>}2=\frac{[{(l1+l2)}^2-L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;m1+\frac{[{(l1+l2)}^2+L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">m</figure-callout>}2\end{array};$

Wherein, m1 and m2 respectively with the sideline load moment of this unit.

Preferably, described first node is positioned at the marginal position of described region of stress concentration.

Preferably, l2 >=l1, l1 is the distance between first node and compare great sideline, this unit load, l2 is the distance between Section Point and first node.

Preferably, l2 ﹤ 1.5l1.

Preferably, described member is tee T welding joint.

The present invention also provides a kind of optimization method of component strength, comprises the following steps:

Step 1, carries out three-dimensional modeling to member;

Step 2, imports finite element analysis software by the three-dimensional modeling data of member and carries out initial analysis, obtains the stress distribution of each unit;

Step 3, adopts the method for claim 1 to carry out stress analysis, obtains the stress analysis value of corresponding units;

Step 4, compares by described stress analysis value and designing requirement the judged result whether acquisition meets design requirement when front part, when described, judgment result is that while meeting design requirement, and assert that the project organization of this member is reasonable, exits; Otherwise the structure of modification member, goes to step 1.

Stress analysis method at member provided by the invention, by member is carried out after finite element initial analysis, unit for stress concentration portion position, at stress distribution gradient visibility point, insert first node, in the unconspicuous position of stress distribution gradient, insert Section Point, adopt the original linear load of piecewise linearity load fitting of distribution to distribute, the analysis result that can try to achieve larger unit size is revised with actual conditions more approaching, has obviously improved reliably the precision that component stress is analyzed; In addition, this method does not need to determine one by one the distribution of load after division unit again, has greatly improved work efficiency simultaneously.

In preferred version of the present invention, first node is positioned at the edge of region of stress concentration, 1.5l1 ﹥ l2 >=l1, l1 is the distance between first node and compare great sideline, this unit load, l2 is the distance between Section Point and first node, the mode of this selection node, analysis result more approaches actual conditions, from the further analysis precision that promoted.

Accompanying drawing explanation

Fig. 1 is a kind of structural representation of typical tee T welding joint;

Fig. 2 for adopt existing common finite element analytical approach with larger unit size the dividing elements schematic diagram to the welding joint of tee T shown in Fig. 1;

Fig. 3 for adopt existing common finite element analytical approach with less unit size the single-row division schematic diagram to the welding joint of tee T shown in Fig. 1;

Fig. 4 is for adopting the resulting stress distribution contrast of the dividing elements method shown in Fig. 2, Fig. 3 schematic diagram.

Fig. 5 is the stress analysis Method And Principle schematic diagram of the member described in embodiment;

Fig. 6 is the stress analysis method flow diagram of the member described in embodiment.

Embodiment

Core of the present invention is to provide a kind of stress analysis method of member, carries out after optimal design on the basis of common finite element analysis, can guarantee on the one hand the precision of stress analysis, can effectively increase work efficiency simultaneously.Carry out on this basis the structural design of member, can meet preferably the needs of engineering reality.Below in conjunction with explanation the drawings and specific embodiments, technical scheme of the present invention is described in further detail, so that those skilled in the art understand better.

Without loss of generality, for the detailed introduction of technical solution of the present invention, still take the element structure shown in Fig. 1 carries out as example.

Component strength optimization method described in present embodiment comprises the following steps:

Step 1: member (tee T welding joint) is carried out to three-dimensional modeling.Three-dimensional modeling adopts the Three-dimensional Design Software of existing maturation to complete, Pro/Engineer for example, SolidWorks etc.

Step 2: the three-dimensional modeling data of member is imported to finite element analysis software (as: LUSAS, MSC.Nastran, Ansys, Abaqus, LMS-Samtech, Algor, Femap/NX Nastran, Hypermesh, COMSOL Multiphysics, FEPG etc.) in, and adopt larger unit size to carry out grid division, utilize finite element analysis software to carry out initial analysis to the stress distribution of above-mentioned member, obtain the stress distribution of each unit, wherein, the linear distribution of the stress distribution of the unit of stress concentration portion position as shown in Z1 in Fig. 4, from stress concentrated position to far-end, stress (load) reduces gradually.

In this embodiment, the length setting of unit is 100 * t=500mm, one side of take is wherein example the thickness of slab center of riser 12 (using divide as separatrix), riser 12 is divided altogether for first module A1 and two unit of second unit A2, and base plate 11 is divided altogether six unit for B1～B6.

Step 3: the stress distribution for the unit of stress concentration portion position is revised, and obtains the multi-line section stress distribution of corresponding units, and then obtains the stress analysis value of corresponding units.

Step 4: above-mentioned stress analysis value and designing requirement are compared to the judged result whether acquisition meets design requirement when front part, judgment result is that while meeting design requirement when described, assert that the project organization of this member is reasonable, exit; Otherwise the structure of modification member (if the size of revising riser 12 is, the height of revising weld seam 13 or width etc.), then, forwards step 1 to and re-starts analysis.

In said method, the committed step that step 3 is technical solution of the present invention, is below described in further detail.

As shown in Figure 6, the stress analysis method of the member described in the specific embodiment of the invention, comprises the following steps:

Step 21: member is carried out to finite element analysis, obtain the linear stress distribution of each unit and the sideline load at these two ends, unit.

The stress distribution of unit A1 of take is example (linear load as shown in Figure 5 distributes), wherein, the length of unit is L, and left end is corresponding to weld seam position in Fig. 4, and right-hand member is corresponding to free end in Fig. 4, left end load (stress) maximum, magnitude of load is f1, right-hand member load (stress) minimum, and magnitude of load is f2, therefore, this unit makes a concerted effort for F1=(f1+f2) * L/2.

Step 22: on the unit of stress concentration portion position A1, insert successively two nodes along the length L direction of unit, these two nodes are defined as respectively first node J1 and the second two node J2.First node J1 and the second two node J2 are divided into first, second, and third totally three subelement Z1, Z2, Z3 successively by unit A1, wherein, first node J1 is positioned at the region of stress concentration on member, stress distribution gradient in this region is obvious, the distance of first node J1 and left end sideline, unit load is l1, the length that is equivalent to the first subelement Z1 is l1, and the sideline load at two ends is respectively ff1 and ff2.Section Point J2 is positioned at outside the region of stress concentration on member, and the stress distribution gradient in this region is not obvious.Distance between Section Point J2 and first node J1 is l2, and the length that is equivalent to the second subelement Z2 is l2, and the sideline load at two ends is respectively ff2 and ff3.So, the length l 3=(L-l1-l2 of the 3rd subelement Z3), the stress distribution on the 3rd subelement Z3 is horizontal linear and distributes, and thinks that the load ff3 on the 3rd subelement Z3 is evenly distributed, ff3=(f1+f2)/2.

Like this, the F2 that makes a concerted effort of first, second, and third subelement is:

$\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">F</figure-callout>}2=(\mathrm{ff}1+\mathrm{ff}2)\&CenterDot;\frac{l1}{2}+(\mathrm{<figure-callout\; id="2"\; label="ff"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">ff</figure-callout>}2+\mathrm{ff}3)\&CenterDot;\frac{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">l</figure-callout>}2}{2}+\mathrm{<figure-callout\; id="2"\; label="ff"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">ff</figure-callout>}2\&CenterDot;l3;$

Step 23, in view of the F2 that makes a concerted effort of, tri-subelements of power F1=of unit, therefore,

$(f1+f2)\&CenterDot;\frac{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">L</figure-callout>}}{2}=(\mathrm{ff}1+\mathrm{ff}2)\&CenterDot;\frac{l1}{2}+(\mathrm{<figure-callout\; id="2"\; label="ff"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">ff</figure-callout>}2+\mathrm{ff}3)\&CenterDot;\frac{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">l</figure-callout>}2}{2}+\mathrm{ff}3\&CenterDot;l3.$

According to the moment of unit, equate with the resultant moment of three subelements again, can obtain:

$\begin{array}{c}\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">f</figure-callout>}2\&CenterDot;\frac{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">L</figure-callout>}}^2}{2}+(f1-f2)\&CenterDot;\frac{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">L</figure-callout>}}^2}{6}=\\ \mathrm{ff}3\&CenterDot;l3\&CenterDot;(l1+\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">l</figure-callout>}2+\frac{l3}{2})+(\mathrm{ff}1-\mathrm{ff}2)\&CenterDot;\frac{{l1}^2}{6}+(\mathrm{ff}3-\mathrm{ff}2)\&CenterDot;\frac{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">l</figure-callout>}2}{2}\&CenterDot;(l1+\frac{2\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">l</figure-callout>}2}{3})+\mathrm{<figure-callout\; id="2"\; label="ff"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">ff</figure-callout>}2\&CenterDot;\frac{{(l1+l2)}^2}{2}\end{array}$

By above-mentioned two equatioies, tried to achieve:

$\begin{array}{c}\mathrm{ff}1=\frac{({l1}^2+l1\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">l</figure-callout>}2+L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;f1+\frac{({l1}^2+l1\&CenterDot;l2-L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">f</figure-callout>}2\\ \mathrm{<figure-callout\; id="2"\; label="ff"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">ff</figure-callout>}2=\frac{[{(l1+l2)}^2-L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;f1+\frac{[{(l1+l2)}^2+L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;f2\end{array}---\left(1\right)$

Step 24, in like manner: establish the sideline load moment that m1, m2 are respectively unit A1;

Mm1, mm2 and mm3 are respectively the sideline load moment of first, second, and third subelement Z1, Z2 and Z3, and mm3 horizontal distribution also equals (m1+m2)/2;

The same have:

$\begin{array}{c}\mathrm{mm}1=\frac{({l1}^2+l1\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">l</figure-callout>}2+L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;m1+\frac{({l1}^2+l1\&CenterDot;l2-L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;m2\\ \mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">mm</figure-callout>}2=\frac{[{(l1+l2)}^2-L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;m1+\frac{[{(l1+l2)}^2+L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;m2\end{array}---\left(2\right)$

Like this, the analytic value that the non-linear stress of first node J1 and Section Point J2 distributes is respectively:

$\begin{array}{c}{\mathrm{\&sigma;}}_{s1}={\mathrm{\&sigma;}}_{m1}+{\mathrm{\&sigma;}}_{b1}=\frac{\mathrm{ff}1}{t}+\frac{6\&CenterDot;\mathrm{mm}1}{{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">t</figure-callout>}}^2}\\ {\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">s</figure-callout>}2}={\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000414283290000031.png"\; state="\{\{state\}\}">m</figure-callout>}2}+{\mathrm{\&sigma;}}_{b2}=\frac{\mathrm{ff}2}{t}+\frac{6\&CenterDot;\mathrm{mm}2}{t^2}\end{array}---\left(3\right)$

In above introduction, using unit A1 as exemplary explanation, other unit, as similar in A2, B1, B2 and A1, no longer repeat to introduce.

Method provided by the invention, the principle of use sectional linear fitting, by the linear distribution on larger unit, it fits to piecewise linearity distribution, then obtains the analytic value that non-linear stress distributes.When large scale structure is carried out to finite element analysis, can first with larger size of mesh opening, analyze, after obtaining the stress distribution of unit, adopt formula (1) and (2) to revise, then redefine actual non-linear stress distribution analytic value according to formula (3), do not need to repartition unit, solution efficiency is high, meanwhile, resulting result and actual stress distribute more approaching, and analysis precision is obviously improved.

Through pilot production, the factor of stress concentration SCF of the root of weld in above-mentioned example is compared to result as follows:

(1) adopt general finite element analysis, the SCF=6.25 trying to achieve while setting the unit size shown in Fig. 2;

(2) the theoretical reference value SCF=2.79 that adopts solid element to try to achieve;

(3) adopt method provided by the invention, ask the SCF=2.82 obtaining.

Obviously, above-mentioned comparing result shows, adopts method provided by the invention, has obviously improved efficiency and precision in FEM (finite element) calculation process, can guarantee the working strength of member, has expanded the applicability of Finite Element Method in engineering application.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (9)

1. the stress analysis method of member, is characterized in that, comprises the following steps:

Member is carried out to finite element analysis, obtain the linear stress distribution of each unit and the sideline load at these two ends, unit;

In the region of stress concentration of the described unit of stress concentration portion position, inserting first node, at region of stress concentration, insert Section Point outward, is three subelements by this dividing elements;

According to the force and moment of described unit respectively with the making a concerted effort and principle that resultant moment equates of three described subelements, determine three described subelements sideline load separately;

The linear stress that the linear stress distribution of multistage forming with the sideline load of three described subelements substitutes this unit distributes, and obtains the stress analysis value of this unit.

2. the stress analysis method of member according to claim 1, it is characterized in that, described first node and Section Point are divided into first, second, and third subelement successively by corresponding unit, wherein, the stress distribution of described the 3rd subelement is for all carrying, and sideline load ff3=(f1+f2)/2, wherein, f1 and f2 are the sideline load at two ends, described unit.

3. the stress analysis method of member according to claim 2, is characterized in that, sideline, two ends load ff1 and the ff2 of described the first subelement calculate by following formula:

$\begin{array}{c}\mathrm{ff}1=\frac{({l1}^2+l1\&CenterDot;l2+L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;f1+\frac{({l1}^2+l1\&CenterDot;l2-L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;f2;\\ \mathrm{ff}2=\frac{[{(l1+l2)}^2-L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;f1+\frac{[{(l1+l2)}^2+L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;f2;\end{array}$

Wherein, the length that L is described unit, l1 is the distance between described first node and compare great sideline, this unit load, l2 is the distance between described Section Point and first node.

4. the stress analysis method of member according to claim 3, is characterized in that, the stress analysis value σ of described first node _s1stress analysis value σ with Section Point _s2by following formula, calculate respectively:

$\begin{array}{c}{\mathrm{\&sigma;}}_{s1}=\frac{\mathrm{ff}1}{t}+\frac{6\&CenterDot;\mathrm{mm}1}{t^2};\\ {\mathrm{\&sigma;}}_{s2}=\frac{\mathrm{ff}2}{t}+\frac{6\&CenterDot;\mathrm{mm}2}{t^2};\end{array}$

Wherein, t is the member thickness that described unit is corresponding, and mm1, mm2 and mm3 are respectively the sideline load moment of first, second, and third subelement, and mm3=(m1+m2)/2;

$\begin{array}{c}\mathrm{mm}1=\frac{({l1}^2+l1\&CenterDot;l2+L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;m1+\frac{({l1}^2+l1\&CenterDot;l2-L^2)}{2\&CenterDot;l1\&CenterDot;(l1+l2)}\&CenterDot;m2\\ \mathrm{mm}2=\frac{[{(l1+l2)}^2-L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;m1+\frac{[{(l1+l2)}^2+L^2]}{2\&CenterDot;{(l1+l2)}^2}\&CenterDot;m2\end{array};$

Wherein, m1 and m2 respectively with the sideline load moment of this unit.

5. the stress analysis method of member according to claim 1, is characterized in that, described first node is positioned at the marginal position of described region of stress concentration.

6. the stress analysis method of member according to claim 5, is characterized in that, l2 >=l1, and l1 is the distance between first node and compare great sideline, this unit load, l2 is the distance between Section Point and first node.

7. the stress analysis method of member according to claim 6, is characterized in that, l2 ﹤ 1.5l1.

8. according to the stress analysis method of the member described in claim 1 to 7 any one, it is characterized in that, described member is tee T welding joint.

9. the optimization method of component strength, is characterized in that, comprises the following steps:

Step 1, carries out three-dimensional modeling to member;

Step 2, imports finite element analysis software by the three-dimensional modeling data of member and carries out initial analysis, obtains the stress distribution of each unit;

Step 3, adopts the method as described in any one in claim 1 to 7 to carry out stress analysis, obtains the stress analysis value of corresponding units;

Step 4, compares by described stress analysis value and designing requirement the judged result whether acquisition meets design requirement when front part, when described, judgment result is that while meeting design requirement, and assert that the project organization of this member is reasonable, exits; Otherwise the structure of modification member, goes to step 1.

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