Solder of dynamic displacement field build model and numeric imitate

In This Article, the Constitutive Equations Of Dynamic Displacement Field Of Welding Process Is Established Based On Thermo-elastic-plastic Theory, and The FEM Analysis Model Of Displacement Field Which Contains Non-linearity Of Material And Variation Of Environment Parameters Is Constructed According To Characteristic Of High Temperature Region.

The Calculation Of Indirectly-coupled Thermo-mechnical Field Is Carried Out By ANSYS.

The Actual Displacement Field Measured By Electronic Speckle Pattern Interferometry Is Compared With The FEM Results, and Excellent Agreement Between The Calculated And Measured Values Is Shown.

Key Words: Dynamic Displacement Field Of Welding, model Building, numerical Simulation preface regards advanced production technology as a medium main component, future solders technical development will move toward " scientific " from " craft " , and solder the development of process imitate technology is its important sign [1] . Since the model of heat conduction of solid of mobile heat source since Rosenthal and the analytic solution that build solder to receive temperature field [2] , numerous welder author considers to solder hard the computer simulation technology of the process, those who be like Japan on Tian Xingxiong is used above all finite yuan the technology was analysed solder the stress of the process and meet an emergency [3] . Soldering at present the imitate object respect of the domain basically includes temperature, displacement, meet an emergency, stress to wait. What produce an effect to integral structure function truly among them is stress and meet an emergency, this ability is simulative final target. But stress and meet an emergency undertake experiment test and verify hard quite (show some detecting the method is more not high temperature resistant ruinous perhaps) , so from whether to suit result test and verify for this one angle, should regard direct imitate as the quantity with displacement field, after the validity that measures to imitate undertakes test and verify, derive result of stress meet an emergency undertakes an analysis. Of equation of a compose build what this compose concerns to build the position with material closely related. Solder process metal component should experience two level: Heat and cool, the meeting on some hour component has look of solid photograph area, fluid area and solid fluid are concomitant area, affecting the equation that uses when computation. Presence of area of solid fluid coexistence is very large agglutinant, accord with stick play plasticity finite yuan, but because solder the cooling rate below the condition is rapid, time of existence of solid fluid area is short, negligible not plan [4] , because this basically considers solid photograph area and fluid photograph area. Heat of obedience of the stress of solid state area, meet an emergency plays plasticity theory, according to waiting to succumb to aggrandizement Von Mises criterion and Prandtl-Reuss flow the heat that the material property of increment theory derivation relies on temperature plays relation of meet an emergency of plasticity increment stress namely increment this compose equation, if type is shown 1 times. ε of D{σ }=[D]d{}-{C}dT (1) in type: [D] : Play plasticity matrix, in stretch area [D]=[De] , in plasticity area [D]=[D]ep=[De]-[D]p among them [De] : Stretch matrix [D]ep- plays vector of coefficient of linear expansion of}- of α of plasticity matrix {to play plasticity to heat, its spread out in detail for: Among them H: Index of sclerosis of meet an emergency: Wait for principle of displacement of empty of effect force basis, build finite the increment expression of yuan of equation is shown 3 times like type. [{R}e of △ of}= of δ of K]e △ {(3) in type: [K]e: Unit stiffness blast [} of δ of E[B]T[D][B]dxdy{of K]e= ∫ ∫ : Bencijia carries (or temperature increment) the displacement increment {R}e that causes: Above of 　 of Tdxdy of E[B]T{C} △ of ∫ of ∫ of {R}e= of △ of vector of force of unit and equivalent node assumes get below premise in certain theory, be as follows suppose: The law of behavior obedience flow inside plasticity area, show sclerosis of meet an emergency; Stretch meet an emergency, plasticity meet an emergency and temperature meet an emergency are disjunctive; The mechanical function of material follows temperature and change; Take no account of agglutinant affect with creep; Material isotropy. Of model of analysis of 2 displacement field build 2.

The maintenance of the builds displacement field geometry model of 1 geometry model and temperature field is consistent, after the temperature field that completes this step is calculated, alternate through unit by temperature field unit unit changeover is structural field unit, delimit unitly of dispenses temperature field keep consistent, if pursue,1 is shown. Graph 1 finite yuan of computation is unit differentiate 2.

The processing 　 of 2 bath heats up action in electric arc when the metal of bath area when next fusing, bath area will enter state of 0 mechanical function, namely all stress meet an emergency will disappear; When bath becomes solid body by liquid change, enter the initiative state that does not have history of meet an emergency. In addition, metal of liquid state bath is right all round the force that solid brings to bear on is very small, right the stress meet an emergency of area distributings to have any effects hardly all round bath. Accordingly, distributing for the stress meet an emergency of area of correct imitate high temperature, the occurrence that must consider bath and disappear, because the bogus of bath area is out of shape,will bring about displacement field imitate to disable otherwise. To this, used method of " of " unit anyway. Its principle is as follows: Right each child the temperature field numerical value of the pace undertakes choosing as a result: The unit that exceeds melting point will make his die, be activationed by " under the unit of melting point " . 2.

3 nonlinear processing solder existing in the process very big nonlinear. Expression is in the following respects: ① geometry is nonlinear: Solder attribute great strain problem. The meet an emergency that great strain is generation pointing to place arrives greatly enough so that the change that causes unit appearance causes stiffness to change, ② material is nonlinear: Point to stress and meet an emergency between nonlinear relation, for example plasticity is the stress with nonlinear existence - meet an emergency concerns; And stick plasticity, creep is meet an emergency and other factor (time, temperature) existence concerns some kind. Analyse medium plasticity material performance for comprehensive consideration, must consider to succumb criterion, flow criterion and sclerotic and mensurable unity. Be aimed at above problem, use the following method: ① uses Full Newton-Raphson method, every undertake balancing iteration, amend stiffness matrix, the Xiang Jiang such as the bilinear that ② application Ansys offers turns model imitate material nonlinear. This type applies to isotropy material, von Mises succumbs criterion and Prandtl-Reuss flow equation apply together (but take no account of Bauschinger effect) . 2.

The article uses 4 analysises technological process ANSYS software undertakes finite yuan of computation. ANSYS offerred way of two kinds of coupling in the light of the analysis of different physics field: Direct coupling and indirect coupling. Analysis of field of strictly speaking temperature and displacement field analysis are direct coupling, but because the experiment proves action of this kind of coupling is very small, ignor so. Used when computation build in child the indirect coupling means on pace level. Namely: Differentiate time between enough Xiaoou (child pace) , advanced travel transient state heats up an analysis inside each interval, after the end that seek solution thermal current gradient the result of the biggest hour stocks unit watch in; Have unit transition next, differentiate with same geometrical model, unit undertake the structure is analysed, the attrib border condition that guides unit expresses result data to regard a structure as the analysis, make analysis of structure of static freedom metabolic. Solder with what this flow has 5 seconds first heat process imitate, undertake agreement the cooling process imitate of 60 seconds later. Heat the order flow of level is shown 2 times like the graph. Graph 3 argon arc decides flow chart of 2 computation analysis the data that the experiment of the article uses the test and verify of result of computation of field of spot welding displacement is LY2 aluminium alloy, test specimen dimension 120 × of 120 × 2mm, solder the method is TIG calm spot welding, solder voltaic 80A, solder voltage 12.

8V. Solder displacement field measurement technique is to stimulate photoelectron to come loose spot interferes a law. Experimental clamping apparatus is shown 3 times like the graph. Graph graph 4 TIG decides sketch map of 3 experiments clamping apparatus spot welding laser comes loose result of spot law test and finite of yuan of computation result contrast pursue the 4 computational results that are field of displacement of TIG calm spot welding and use laser electron to come loose spot interference law gets what measure an outcome actually compare (graphic representation is complete displacement. The error with can see from inside the graph experimental result and computational result are existing certain, this may be cause by next reasons: 1.

The tall tepid physics of material and mechanical performance data are the be not accorded with with real data and brings calculation that uses extrapolation to get error; 2.

The heat source in numeric imitate is to bring to bear on strictly at board of the center, and because cannot locate accurately,be in in real test, and cannot make sure electric arc and workpiece are strict and perpendicular. So, affected the computational result of displacement field. The article uses 4 verdict the soldering that laser electron comes loose to be measured actually what spot interference measures a technology is dynamic displacement field and finite yuan computation undertook comparative as a result, the result proves computational result and be identical of actual measurement result are good. This explains the article uses those who play place of plasticity sex theory to build to solder the model of field of process trends displacement is correct. CNC Milling CNC Machining