add parameter table, correct typo

Author: mkraska

NonLinear/3PB/README.md

@@ -21,6 +21,18 @@ domain is reduced to a quarter due to symmetry.
 
 ## Pre-Processing
 
+
+| Parameter | Value | Meaning |
+| :------------- |  :------------- | :------------- |
+| `th` | 4 | wall thickness in mm |
+| `wi` | 200 | width of the profile in mm|
+| `he` | 50 | height of the profile in mm |
+| `le` | 250 | half span of the supports in mm |
+| `l2` | 40 | extra length beyond the supports in mm |
+| `ro` | 20 | radius of the intenter in mm |
+| `ra` | 6 | outer fillet radius of the profile in mm |
+| `cs` | 10 | dimension of the contact region in mm |
+
 You may adjust the parameter values in the file [par.pre.fbl](par.pre.fbl) and then run
 ```
 > param.py par.pre.fbl

NonLinear/3PB/par.pre.fbl

@@ -3,7 +3,7 @@
 # <he=50>
 # <le=250>
 # <l2=40>
-# <lr=wi+2*th> lenthe of the indenter
+# <lr=wi+2*th> length of the indenter
 # <ro=20> radius of the intenter
 # <ra=6>
 # <cs=10> width of contact region