Suppose you do not have Xcode running, but want to view crash logs of your simulator, you can do that easily by visiting
~/Library/Logs/DiagnosticReports/
Here all crash log files can be found with .crash extension.
Note: you need to launch your app without Xcode in order to have the log updated.
Sources
Crash logs generated by iPhone Simulator? – Stack Overflow. http://stackoverflow.com/questions/1864479/crash-logs-generated-by-iphone-simulator