after pip successful installed: ModuleNotFoundError

I had same problem (on Windows) and the root cause in my case was ANTIVIRUS software! It has "Auto-Containment" feature, that wraps running process with some kind of a virtual machine.
Symptoms are the same: pip install <module> works fine in one cmd line window and import <module> fails when executed from another process.

When this happened to me (on macOS), the problem turned out to be that the python installation I specified at the top of my script.py was not the same python installation that conda/pip were using on the command line.

To get the command line and my script to match up, I changed the header in my script.py to just use:

#!python

Then when I ran ./script.py on the command line, everything finally worked.

Wherever you're running your code, try this

import sys

sys.path
sys.executable

It might be possible that you're running python in one environment and the module is installed in another environment.

Since you are using python 3.6.1, you may need to specify the type of python you want to install simpy for. Try running pip3 install simpy to install the simpy module to your python3 library.