If you dont have LoadRunner available to you, yet you want to stress test your TM1 Application then its worth having a look at Apache JMeter.
JMeter you can download for free and then follow the instructions on IBM DeveloperWorks here:
http://www.ibm.com/developerworks/library/ba-pp-infrastructure-cognos_specific-page675/ba-pp-infrastructure-cognos_specific-page675-pdf.pdf
