Search results for query: *

IDS, thank you!

Everyone, thanks for the reply! I gave a simplified example. What I really want is to find a word in a line and change another word in the same line. This example will be more clear: TEMP 1 100001 56 TEMP 1 100002 56 TEMP 1 100003 34 TEMP 1 100004 67 ...

I try to use VBA to read and write a text file without using "Cells". How can I find a "word" in a text file and change this word and output another text file? For example, I want to find all "structural" in the following text file and change it to "nonstructural". Suppose that size of the file...

Everyone, thanks for the input! The vehicle is different than a conventional non-rigid airship. The vehicle is equipped with air landing cushions for vertical landing. Suction force can not be applied before the vehicle fully lands on ground. The cushion pressure can be controlled to avoid...

I don't analyze the descent condition. The FE model is used for analyze the state when the vehicle touch the ground with a constant speed and also it is a static analysis. In the model, the vehicle is given an inertia loads due to the negative acceleration (speed reduces from V to zero). My...

Thanks for the reply. Yes, drag is ignored since the speed is very small. I used static analysis of FE modle to acceleration or impact force that the vehicle can stand. Landing cushion is not in the FE model. Then, according to energy equation 1/2MV^2=Fd=M*a*d, I can calculate a speed with the...

How to calculate the impact force when an lighter-than-air vehicle performs Vertical Landing? Actually, the vehicle lands vertically on the ground using air cushions. I tried to establish a speed corresponding to the impact forces. The impact forces are obtained from max ground reaction force...

Blas, Thanks for the reply. It is not easy to create many RBE3 manually. To make same mesh at both surface of solids might not be applicable to two solids. I just found out that there is a contact option in PATRAN Load/BC. But the input file can only be solved by MD NASTRAN, not regular...

Thank you, Onda. I don't have MD Nastran. I'll check about that.

Onda, Greg, thanks for the reply. It sounds that the following methods can be used to bond two surfaces: 1.merge coincident nodes 2. CWELD connection 3. CFAST connection 4. RBE3 (someone suggest me this method) All these ways need manual creation of grid points at the surfaces. I was wondering...

Does PATRAN/NASTRAN have the capability to bond two surfaces of two solids together? I tried to model an assembly consisting of two parts. The two parts share one surface. How can I glue these two together in order to obtain same nodes and mesh at the bonded surface?

Blas, Thanks for the reply. I know the meaning of margin of safety and how to calculate. But I don't know how I can get the first 10 maximum and minimum values of margin of safety by using the statement MAXMIN (DEF) TTTT (BEAM,10) MAXALG(10) MINALG(10) in NASTRAN input file? What do I use to...

How to write NASTRAN statement for output of safety margin: MAXMIN (DEF) TTTT (BEAM,10) MAXALG(10) MINALG(10)? I know the how to write the ourput for stress and forces but don't know which word in NASTRAN is used for safety margin (replacing TTTT in the above statement). I tried to find it in...

Thank you, Blas!

Thanks, onda.

Thanks a lot, everyone! I solved a simple beam problem, which has some part on the ground. From Utilities->Applications->Linear Gaps, I used Gap to Ground option. The result shows reasonable. The beam elements contacting the ground can deform above the ground but not into the ground.

Blas, Thanks for the reply. IF I constrain all the rotational DOF of all truss nodes, the problem can be solved and there is no singularity. In reality, I don't need to form triangles of beams/rods to make the truss structure stable, some pretension cables can be used to make the truss...

Johnhors, Onda, Thank you for the reply. I used CROD element to model the truss because the truss members can only hold tension and compression load due to the joint design. If I constrain 4,5,6 DOF of each grid point, there is no singularity. My question is that "Is this a correct way to...

Onda, Thank you for the helpful post. In order to test 3D modeling, I tried an example of a simple 3D cantilever beam. The picture is attached, and the beam is fixed at one end and forces are applied on the top surface. (My Patran has problem of generating jpg file and I can get bmp file, not...

When I used Cbar and constrain the 4th 5th and 6th DOF of each grid point, the model will be solved. But my question is that the structure is a 3D truss, some grid points might be able to rotate with respect to the original coordinate system. Or I can make the assumption that the members can...