Quodsi Version: 2026.02.22

Written By Renee Thiesing

Summary

This release introduces full Activity Failure Modeling using Mean Time Between Failures (MTBF) and Mean Time To Repair (MTTR). Activities can now be configured to fail periodically, interrupting in-progress entities and resuming them after repair. This enables more realistic modeling of downtime and system reliability within discrete-event simulations.

New Features

Activity Failure Modeling (MTBF/MTTR) 

Overview
 Activities can now be configured with failure and repair behavior. When a failure occurs, entities currently being processed are interrupted and resume with their remaining processing time once the repair is completed.  VideoClip_Downtime

User Interface

  • New Failure Properties tab in the Activity Editor

  • Enable/disable failure modeling via checkbox

  • MTBF duration editor

  • MTTR duration editor

  • Failure clock mode selector

  • Repair resource requirement selector

  • Fully supported via JSON model import

Simulation Runtime Behavior

  • Entities in a failed activity are interrupted and resume with remaining processing time after repair

Metrics & Reporting

Failure-related metrics are now tracked at both the activity and activity-entity levels across single and multi-replication runs.

New fields added to CSV and Excel exports:

  • Total Time in Failure

  • Average Failure Time

  • Total Failure Time

Failure metrics are available in:

  • ScenarioAnalysisDashboard chart dropdowns

  • Cross-replication summary tables

Renee Thiesing