LS-DYNA beginner's experience

1.LS-DYNA brief introduction  

LS-DYNA It is the most famous general explicit dynamic analysis program in the world , Be able to simulate various complex problems in the real world , It is especially suitable for solving various two-dimensional problems 、 High speed collision of three-dimensional nonlinear structures 、 Nonlinear dynamic impact problems such as explosion and metal forming , At the same time, heat transfer can be solved 、 Fluid and fluid solid coupling problems . It is widely recognized as the best analysis software package in the field of engineering applications . Numerous comparisons with experiments have confirmed the reliability of the calculation .

from J.O.Hallquist Preside over the completed development DYNA The program series is recognized as the originator and theoretical forerunner of explicit finite element program , Is all the current explicit solvers （ Including explicit plate forming procedures ） The basic code for .1988 year J.O.Hallquist establish LSTC company , Introduction LS-DYNA Program series , And in 1997 The year will be LS-DYNA2D、LS-DYNA3D、LS-TOPAZ2D、LS-TOPAZ3D Wait for the program to compose a software package , be called LS-DYNA.PC edition LS-DYNA The default pre and post-processing is ETA The company's FEMB, In addition, another pre-processing and post-processing software is also included LS-PREPOST.LS-DYNA The versions of are divided into ：950 edition ,960 edition ,970 edition ,971 Version and 980 edition （ Will release ） etc. , At the same time, each version has a more detailed classification , Such as ：LS-DYNA 971 R3.1.exe and LS-DYNA 971R4.2.exe etc. . These classifications are based on the version of the solver .

2. Application LS-DYNA The whole process of analyzing the problem

a. Turn the real process into a program model （ You have to figure out what you already know , What else can we find , What do you want to know , What kind of model should be built ）;( Know what model to build , above all , But it's easy to ignore . Whether the final calculation result is correct , This step basically determines ).    

b. Before processing （ drawing , modeling , Set boundary ）（ Build a model , The resulting K file , It contains all the model data ）         

c. Calculation （ Solving the problem , take k File submission DYNA Solver calculation ）        

d. post-processing （ Read out the results you want to know ）（ Extract the data or animation you care about ）       

e. Write a report （ Your initial and ultimate goal ）（ According to your research , Analyze and summarize the data , It's not about software , It's your own business ）.

3. ANSYS/LS-DYNA And LS-DYNA The relationship between

1996 year LSTC And ANSYS Launched in cooperation with the company ANSYS/LS-DYNA, With ANSYS As a pre and post-processing , With LS-DYNA The solver （ That is to say ls960.exeor ls970.exe etc. ,ANSYS/LS-DYNA Different versions of , The corresponding solver is different , The solver is in ANSYS The installation directory bin\intel Under the folder ）, This solver and LSTC Formula issued by LS-DYNA There is no difference between the corresponding version and the solver version . And what people usually say PC edition LS-DYNA refer to LSTC Software packages issued by our company , With LS-DYNAManager As a management platform , You can call the default pre-processing software FEMB（ETA company ） And pre - and post-processing software LS-PREPOST（LSTC company ）, And can call ls960.exe orls970.exe etc. .

Solver for the established model file k File to calculate . therefore , Their relationship is as follows ：    

a. In terms of computing functions , There is no difference between the two ; All use ls960.exe or ls970.exe And so on .

b. From the perspective of the issuing company ,ANSYS/LS-DYNA yes ANSYS and LSTC Jointly launch ,PC edition LS-DYNA from LSTC Introduction .        

c. In the past, it was said that ,ANSYS/LS-DYNA With ANSYS As a pretreatment ,PC edition LS-DYNA The default preprocessing is FEMB and LS-PREPOST.

d. In terms of post-processing ,ANSYS/LS-DYNA With ANSYS and LS-PREPOST（ In the same directory as the solver ）,PC edition LS-DYNA With LS-PREPOST As a post-treatment （ You can also set keyword output ANSYS Post processing format of ）   

As can be seen from the above analysis ,DYNA solver （ls960.exe or ls970.exe） Is the core of software , Pretreatment can be arbitrary , Finally, we need to get the key words k file . There is no problem with manual writing . in addition , Such as HYPERMESH(A06：HyperWorks),TUREGRID(A22：TrueGrid) And so on can be used as pre-processing software , If you know more about keywords ,ABAQUS Wait for any output unit , The finite element of node information can be used as your pre-processing software . I use it a lot ABAQUS As a pretreatment , modeling , Meshing , Export node , Unit information file inp file , take inp Change it to K File format , Read in again FEMB Set relevant parameters such as material and contact . Finally submit DYNA Solver calculation . 

4. Use LS-DYNA The best knowledge before

Before using commercial software , It is best to have a basic knowledge ：   

a. Basic theory and thought of finite element .     

b.LS-DYNA The basic process of analyzing problems .    

c.LS-DYNA The characteristics and application scope of .     

d. The most important thing is to have a clear understanding of the problems you are studying （ Not stay in “ Purpose ” On , But to the implementation details , If it is a thermal problem , Acoustic problem or mechanical problem , Or their coupling problem ; Is it a static problem or a dynamic problem , What are the characteristics of materials in the problem ？ Is only considering flexibility , Still consider plasticity , Creep , crack , strain rate , Temperature etc. , Only have a clear understanding of the problems they study , These questions can be answered , And you can get the result you want ）. 

5.LS-DYNA How to get started quickly for beginners   

The following are just personal opinions , For reference only ：       

a. Choose an example similar to your own research problem , Look in the relevant books , Or go online to find .      

b. Process by instance , Do it step by step by yourself , Do with questions （ Such as ： What is the role of each step , If you really don't understand, you can put it first , What can be understood must be understood ）.

c. After the model is built , Submit calculation （ Be familiar with the operation process of solution ）.       

d. After the calculation , According to the example , After treatment , And check whether the results are consistent with others .           

e. After all the above processes , open k file , Yes k Understand the internal format and relationship of the file , You can refer to related books .       

f. Combined with the understanding of examples , Understand each keyword of the instance design , Do not understand the reference keyword manual .（ Not many keywords are involved , The main ones are generally 10 about ）, Match the keyword with the corresponding GUI Operation and function , To realize . Don't ask for more , One numerical example is enough , If you are not sure , Take another example , Verify your experience . After the above process , It can let you know the core part of the software as soon as possible , Many problems are not problems .