Search for:
Base failures that cause more than one violation of safety goal
Explanation:
Base failures will be searched for that are linked to two or more violations of safety goals or are connected with the same violation of safety goal via single-point fault paths or multi-point fault paths.
Example:
Abbreviations:
- The shown sample structure consists of three structure elements. Two safety goals
each with one violation of safety goal 
each are assigned to the root
element. The other two structure elements SE and BSE have functions and failures assigned.
- In the following failure graph, you can see how the base failures BF are linked to the violations of safety goals.
- Two placeholders for the failure type are automatically assigned in the IQ Software to a violation of safety goal. That is shown in the failure graph and the failure net. If you anchor a violation of safety goal in the failure graph or the failure net these placeholders for failure types will automatically show next to the violation of safety goal in the direction of causes. The failure types tell if the failures leading to a violation of safety goal according to ISO 26262 are single-point faults or multiple-point faults.
- The considered Quality Rule (QR) detects base failures (BF), which are either linked to two or more different violations of safety goals or linked to the same violation of safety goal via the single-point fault and multiple point fault path. The following search result is obtained from analyzing the failure graph above:
Search result:
The two base failures BF1 and BF2 are marked as hits.
BF1 is linked to both violatiosn of safety goals TSG1 and TSG2 and thus meets the first of the two QR filter conditions. BF2 has only one link to a violation of safety goal, but the way leading there goes through the single-point fault path as well as the multiple-point fault path. BF2 therefore meets the second of the QR filter conditions.
BF3 and BF4 do not meet any of the QR filter conditions and are therefore not included in the search result.