1. 1.FMEA on the Tent Testing Experiment Tent testing experiment, used to develop design guidelines to install tents is the system under consideration FMEA of the tent testing experiment generated sixteen significant failure modes Confidence Analysis on Failure Modes generated by FMEA on a system Somaiah Thimmaiah ▪ Joshua Summers Graduate Research Assistant ▪ Clemson University ▪ sthimma@clemson.edu Motivation Failure Modes and Effect Analysis (FMEA) is a tool used in product development, reliability testing, and operations management for analysis of failure modes within a system FMEA of a system generates significant failure modes with varying criticality Is there a “Specific number of significant failure modes” to be considered before the system is discarded or modified to increase reliability? Objectives To generate failure modes with comparable level of confidence To learn the variation of confidence of an engineer on a system as the number of failure modes of the system increases To learn the change in confidence level when failure modes are presented with controls 2. Preliminary Study A. Select failure modes with comparable level of confidence A study is conducted on 28 mechanical engineering students Each student is given a packet containing five failure modes Students answered the question, “Despite the failure modes, how confident are you that the test procedure will work?” Confidence vs. Individual failure modes B. Results of preliminary study The average of the individual confidence level for each failure mode is presented in the above graph A combined analysis is conducted and the failure modes that fall within a confidence range of 75% - 55% are selected for further investigation Seven failure modes are selected to learn the variation of confidence 3. The Experiment 117 general engineering students participated in the study A presentation on FMEA and Tent Testing experiment is used for training the students before conducting the experiment Each student is given a packet containing four forms with increasing number of failure modes Form 1: One failure mode, Form 2: Three failure modes, Form 3: Five failure modes, Form 4: Seven failure modes Each form had the question “Despite the failure modes, how confident are you that the test procedure will work?” Students marked their confidence on a linear scale at the bottom of each form 4. Results of the experiment A.Confidence vs. Failure modes The students showed decreasing level of confidence as the number of significant failure modes increased Their confidence on the procedure varied from 75% to 25% as the failure modes increased B. Confidence vs. Failure modes The confidence level decreased in both the cases (with and without control) as the number of failure modes increased The confidence level for both cases is comparable for one failure mode and seven failure modes 5. Future Work Regression analysis to derive an equation for the curve. Predictive analysis: To predict future trends and behavior patterns Confidence Interval Estimate the decrease in confidence for every failure mode Come up with specific number of modes for a particular confidence interval. Sl # Failure Modes AReleasing caster from grey frame using a hydraulic jack. BSwaying of bars in the A frame while moving to the test location. CSwaying of ballast while moving with an A frame to the test location. DConnection failure between data acquisition system and load cell. EBreakage of winch cable. FControl of winch by the operator during drag test. GCollection of surface material below the ballast during a drag test. HIrregular ground surface during drag test. IInsertion of hook from the load cell to the ballast. JForgetting to weigh the ballast at the end of the test procedure. KForgetting to calibrate the load cell. LForgetting to calibrate the data acquisition system. MPositioning of load cell during calibration. NMovement of the grey frame during drag test. ORope which prevents ballast from swaying breaks. PUse of winch by different operators. Sl #Failure Modes CSwaying of ballast while moving with an A frame to the test location. GCollection of surface material below the ballast during a drag test HIrregular ground surface during drag test IInsertion of hook from the load cell to the ballast MPositioning of load cell during calibration NInstability in grey frame during drag test ORope which prevents ballast from swaying breaks