Shock and Vibration

Electronic equipment can be subjected to many different forms of vibration over a wide range of frequencies and acceleration levels. All electronic equipment will be subjected to some type of vibration during its lifetime. If the vibration is not due to an active association with a machine or a moving vehicle, then it may be due to transportation of equipment from a manufacturer to a customer. Vibration is usually considered to be an undesirable condition because it can produce many different types of failures in electronic equipment. Mechanical vibrations can have different sources. In vehicles such as automobiles, trucks, and trains, most of the vibration is due to the rough surfaces over which these vehicles travel. In airplanes, missiles, and rockets, the vibration is due to jet and rocket engines and aerodynamic buffeting. Portable electronic devices such as pagers, palm-top organizers, and compactly designed cell phones are also vulnerable to damage from mechanical shock and vibration. With an indadvertent drop from a desk or bump against a wall, components can collide and render the device inoperable. Over a period of time, the post-shock ringing vibration can fatigue boards and connectors, which creates hard to spot electrical problems. Therefore, the testing of the electronic assemblies should include shock and vibration analysis.

Portable products face the challenges of ever increasing functional density, shorter product cycles, and pressure to reduce costs. Increasing functional density has led to the explosive growth in chip scale package (CSP) usage. The expected life span for a portable product is short compared to many other product categories. However, portable products must survive multiple drops. The decreasing I/O pitch of CSPs, and the resulting smaller pads and solder joints, make the drop requirement more challenging. There are two approaches to improving drop reliability. The first approach involves altering the mechanical design of a product in order to minimize the shock and flexing of the printed circuit board that occurs when the product is dropped. The second approach involves utilizing underfills to mechanically reinforce the CSP solder joints. Consequently, the development of a robust mechanical design, capable of resisting multiple drops, is the preferred approach. Electronics inside of portable electronic products may be subjected from a few hundred Gs to thousands of Gs during an accidental drop from ear level (on average, approximately a 5 ft. drop height). The use of an experimental approach to test out every possible design variation, and identify the one that gives the maximum design margin, is often not feasible because of product development cycle time and cost constraints. There is a fundamental need for understanding and predicting the electronic failure mechanics in shock and drop impact. Figure 1 shows the drop orientation of printed circuit board assembly in vertical and horizontal (JEDEC) orientations.

Transient dynamic deformation of the test boards is the wave propagation problem. The explicit finite element model of drop impact of the test board under zero-degree-JEDEC drop orientation is shown in Figure 2. The JEDEC specifications require that the PCB be mounted with packages facing downwards, and mounted on a rigid base with the help of four-corner standoffs. The peak acceleration for this test is 1500 Gs at 0.5 ms half-sine pulse. The transient drop event is modeled using the commercially available finite element code Abaqus ®.

Lall, P., Pandurangan, A., Dornala, K., Suhling, J., Deep, J., Non-Perpendicular High-G Shock on Potted Fine Pitch Electronics Under Sustained High Temperature Aging, Proceedings of the 2021 IEEE 20th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, pp. 708-718, June 1-4, 2021.

Lall, P., Thomas, T., Blecker, K., Feature Vector Identification and Prognostics of SAC305 PCBs for Varying G-Levels of Drop and Shock Loads, Feature Vector Identification and Prognostics of SAC305 PCBs for Varying G-Levels of Drop and Shock Loads, Proceedings of the 2021 IEEE 20th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, pp. 659-669, June 1-4, 2021.

Lall, P., Thomas, T., Blecker, K., RUL estimations of SAC305 solder PCBs under different conditions of temperature and
vibration loads, Proceedings of the 2020 IEEE 19th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, pp. 1340-1349, July 21-23, 2020.

Lall, P., Pandurangan, A., Dornala, K., Suhling, J., Deep, J., Effect of shock angle on solder-joint reliability of potted assemblies under high-G shock, Proceedings of the 2020 IEEE 19th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, pp. 1328-1339, July 21-23, 2020.

Lall, P., Thomas, T., Suhling, J., Blecker, K., Health monitoring and feature vector identification of failure for SAC305 Solder PCBs under
shock loads up to 10,000g, Proceedings of the 2020 IEEE 19th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, pp. 932-944, July 21-23, 2020.

Lall, P., Thomas, T., Suhling, J., Blecker, K., Prognostication of Accrued Damage and Impending Failure Under TemperatureVibration in Leadfree Electronics, Proceedings of the 2019 IEEE 69th Electronic Components and Technology Conference, Las Vegas, NV, pp. 505-514, May 28-31, 2019.

Lall, P., Dornala, K., Suhling, J., Deep, J., Lowe, R., Effect of Dielectric Material on the Reliability of 3640 MLCC Capacitors under
High-G Shock Loads, Proceedings of the 2019 IEEE 18th  Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, Las Vegas, NV, pp. 1037-1046, May 28-31, 2019.

Lall, P., Dornala, K., Suhling, J., Deep, J., Lowe, R., Cohesive Zone Modeling and Damage Prediction of Interfacial Delamination in Potted Electronics Subjected to High-G Mechanical Shock, Proceedings of the 2019 IEEE 18th  Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, Las Vegas, NV, pp. 1030-1036, May 28-31, 2019.

Lall, P., Pandurangan, A., Dornala, K., Suhling, J., Deep, J., Lowe, R., Effect of Shock Pulse Variation on Surface Mount Electronics under High-G Shock, Proceedings of the 2019 IEEE 18th  Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, Las Vegas, NV, pp. 586-594, May 28-31, 2019.

Lall, P., Kothari, N., Deep, J., Lowe, R., Analysis of Progressive Damage in Fuze Electronics using Micro-Computed Tomography and Finite Element Models, Proceedings of the IEEE 2018 Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm2018), San Diego, CA, pp. 1160-1168, May 29-June 1, 2018.

Chen, J., Nguyen, Q., Roberts, J.C., Suhling, J.C., Jaeger, R.C., Lall, P., Moisture-Induced Die Stresses in PBGA Packages Exposed to Various Environments, Proceedings of the IEEE 2018 Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm2018), San Diego, CA, pp. 1112-1119, May 29-June 1, 2018.

Lall, P., Yadav, V., Suhling, J., Locker, D., Effect of Prolonged Storage on High Strain Rate Mechanical Properties of SAC-Q Leadfree Solder at High Operating Temperature, Proceedings of the IEEE 2018 Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm2018), San Diego, CA, pp. 1296-1308, May 29-June 1, 2018.

Lall, P., Zhang, D., Yadav, V., Suhling, J., Locker, D., Effect of Temperature on the High Strain Rate Properties of SAC Leadfree Alloys at Temperatures up to 200°C, Proceedings of the IEEE 2016 Electronic Components and Technology Conference (ECTC2016), Las Vegas, NV, pp. 1924-1932, May 31-June 3, 2016.

Lall, P., Dornala, K., Lowe, R., Foley, J., Survivability Assessment of Electronics Subjected to Mechanical Shock Up to 25,000g, Proceedings of the ITHERM 2016, Las Vegas, Nevada, pp. 507- 519, May 31- June 3, 2016.

Lall, P., Kothari, N., Foley, J., Deep, J., Lowe, R., A Novel Micro-CT Based Finite Element Modeling Technique to Study Reliability of Densely Packed Fuze Assemblies, Proceedings of the ITHERM 2016, Las Vegas, Nevada, pp. 456- 464, May 31- June 3, 2016.

Lall, P., Dornala K., Suhling, J., Lowe, R., Foley, J., Life Prediction and RUL Assessment of Fine Pitch Solder Joint Fuze Electronics Under Mechanical Shock Loads Up To 50,000g, Proceedings of the 66th ECTC, Las Vegas, Nevada, pp. 232- 244, May 31- June 3, 2016.

Lall, P., Dornala, K., Zhang, D., Xie, D., Zhang, A., Transient Dynamics Model and 3D-DIC Analysis of New-Candidate For JEDEC JESD22-B111 Test Board, Electronic Components and Technology Conference, 64th ECTC, pp. 85-99, Orlando, FL, May 27-30, 2014.

Lall, P., Gupta, P., Goebel, K., Decorrelated Feature Space and Neural Nets Based Framework for Failure Modes Clustering in Electronics Subjected to Mechanical Shock, IEEE Transactions on Reliability, Vol. 61, No. 4, pp. 884-900, December 2012.

Lall, P., Lowe, R., Goebel, K., Prognostication Based on Resistance-Spectroscopy and Phase-Sensitive Detection for Electronics Subjected to Shock-Impact, ASME J. Electron. Packag. 134, 021001-1 to 021001-10, 2012.

Lall, P., Gupta, P., Angral, A., Anomaly Detection and Classification for PHM of Electronics Subjected to Shock and Vibration, IEEE Transactions On Components, Packaging And Manufacturing Technology, DOI: 10.1109/TCPMT.2012.2207460 , Vol. 2, No. 11, pp. 1902-1918, 2012.

Lall, P., Lowe, R., Goebel, K., Prognostics Health Management of Electronic Systems Under Mechanical Shock and Vibration Using Kalman Filter Models and Metrics, IEEE Transactions On Industrial Electronics, Vol. 59, No. 11, November 2012.

Lall, P., Lowe, R., Goebel, K., Health Monitoring of Leadfree Electronics Under Mechanical Shock and Vibration with Particle Filter Based Resistance Spectroscopy, SMTA Journal, Volume 24, Issue 4, pp. 19-32, 2011.

Lall, P., Shantaram, S., Kulkarni, M., Suhling, J., SIF Evaluation Using XFEM and Line Spring Models Under High Strain Rate Environment for Leadfree Alloys, ASME InterPACK, pp. 1-17, Portland, Oregon, USA, July 6-8, 2011.