Knowledge Based Qualification Process to Evaluate Vibration Induced Failures in Electronic Components

Author(s):  
Karumbu Meyyappan ◽  
Milena Vujosevic ◽  
Qifeng Wu ◽  
Pramod Malatkar ◽  
Charles Hill ◽  
...  

Electronic products used in autonomous vehicles can be subjected to harsh road conditions. Transportation induced vibration is one such reliability risk to be addressed as part of qualification. Vibration use data and reliability models are very extensively studied for fully packaged systems exposed to vibration risks during shipping. MIL-STD-810G and ISTA4AB are some of the industry standards that address these risks. On the other hand, USCAR-2 and GMW-3172 are couple of standards that may be more relevant for electronics used in automotive applications, where electronic components are exposed to vibration risks during their entire lifetime. Even though the usage model and duration for fully packaged systems in shipping and automotive electronics are different, the source of energy (road conditions), driving the risks are similar. The industry standards based damage model appear to be generic, covering a wide variety of products. In this paper, a knowledge based qualification (KBQ) framework, is used to map use conditions to accelerated test requirements for two failure modes: solder joint fatigue and socket contact fretting. The mechanisms chosen are distinct with different damage metric and drivers. The KBQ obtained qualification requirements were discussed relative to standard requirement with the objective to verify how well industry standard models reflect field reliability risks. For the chosen failure mechanisms and use condition data, it was observed that the industry standards lead to erroneous conclusions about vibration risk in the field.

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Karumbu Meyyappan ◽  
Milena Vujosevic ◽  
Qifeng Wu ◽  
Pramod Malatkar ◽  
Charles Hill ◽  
...  

This paper intends to address an important gap between reliability standards and the physics of how components respond to real use conditions using a knowledge-based qualification (KBQ) process. Bridging the gap is essential to developing test methods that better reflect field performance. With the growth in importance of automotive market and the wide usage of electronics in this market, vibration-induced failures was chosen for this study. MIL-STD-810G and ISTA4AB are couple of industry standards that address the risk of shipping finished goods to a customer. For automotive electronic products that are exposed to vibration conditions all through their life, USCAR-2 and GMW3172 are more relevant. Even though the usage models and transportation duration for shipping fully packaged systems is different from automotive electronics, the source of energy (road conditions), driving the risks, are similar. The industry standards-based damage models appear to be generic, covering a wide variety of products and failure modes. Whereas, the KBQ framework, used in this paper, maps use conditions to accelerated test requirements for only two failure modes: solder joint fatigue and socket contact fretting. The mechanisms were chosen to be distinct with different damage metric and drivers. The process is intended to explain how industry standards reflect field risks for two of the risks relevant for automotive electronics.


Author(s):  
Pradeep Lall ◽  
Vikas Yadav ◽  
Di Zhang ◽  
Jeff Suhling

Current trends in the automotive industry point to increasing role of electronics for vehicle control, safety, efficiency and entertainment. Examples include lane-departure warning systems, collision avoidance systems, vehicle stability systems, and drive assist systems. Many of the automotive electronics systems are located under the hood of the vehicle mounted directly on engine or on transmission with sustained exposure to temperatures greater than 150°C in conjunction with vibration. Solder joint fatigue is a dominant failure modes under high-temperature vibration. Industry migration to lead-free solders has resulted in a proliferation of a wide variety of solder alloy compositions many of which are based on formulation of Sn, Ag and Cu. While it is well known that solder interconnects, accrue damage much faster when vibrated at elevated temperatures, the models for assessment of life under simultaneous temperature and vibration are scarce. State-of-art reliability models for solder joints focus on single stresses of vibration or thermal cycling. There is need for models for evaluating the survivability of leadfree solder assemblies to ensure 10-years, 100,000 miles life in automotive environments. In this paper, a new model has been proposed for life prediction of electronics under simultaneous temperature-vibration.


Author(s):  
Sven Rzepka ◽  
Alexander Otto ◽  
Dietmar Vogel ◽  
Rainer Dudek

The revolutionary changes in automotive industry towards fully connected automated electrical vehicles necessitates developments in automotive electronics at unprecedented speed. Signal, control, and power electronics will heterogeneously be integrated at minimum space with sensors and actuators to form highly compact and ultra-smart systems for functions like traction, lighting, energy management, computation, and communication. Most of these systems will be highly safety relevant with the requirements in system availability exceeding today’s already high automotive standards. Other than the human drivers of today, passengers in the automated car do not pay constant attention to the driving actions of the vehicle. Hence, reliability research is massively challenged by the new automotive applications. Guaranteeing the specified lifetime at statistical average is no longer sufficient. Assuring that no failure of an individual safety relevant part occurs unexpectedly, becomes most important. The paper surveys the priority actions underway to cope with the tremendous challenges. It highlights practical examples in all three directions of reliability research. i) Experimental reliability tests and physical analyses: New and highly efficient accelerated stress tests are able to cover the complex and multi-fold loading situation in the field. New analytics techniques can identify the typical failure modes and their physical root causes. ii) Virtual techniques: Schemes of validated simulations allow capturing the physics of failure proactively in the design for reliability process. iii) Prognostics health management (PHM): A new concept is introduced for adding a minimum of PHM features at the various levels of automotive electronics to provide functional safety as required for autonomous vehicles. This way, the new generation of reliability methods will continuously provide estimates of the remaining useful life (RUL) for each relevant part under the actual use conditions to allow triggering maintenance in time.


2018 ◽  
Vol 140 (1) ◽  
Author(s):  
Sven Rzepka ◽  
Alexander Otto ◽  
Dietmar Vogel ◽  
Rainer Dudek

The revolutionary changes in automotive industry toward fully connected automated electrical vehicles necessitate developments in automotive electronics at unprecedented speed. Signal, control, and power electronics will heterogeneously be integrated at minimum space with sensors and actuators to form highly compact and ultra-smart systems for functions like traction, lighting, energy management, computation, and communication. Most of these systems will be highly safety relevant with the requirements in system availability exceeding today's already high automotive standards. Unlike the human drivers of today, passengers in the automated car do not pay constant attention to the driving actions of the vehicle. Hence, reliability research is massively challenged by the new automotive applications. Guaranteeing the specified lifetime at statistical average is no longer sufficient. Assuring that no failure of an individual safety relevant part occurs unexpectedly becomes most important. The paper surveys the priority actions underway to cope with the tremendous challenges. It highlights practical examples in all three directions of reliability research: (i) Experimental reliability tests and physical analyses: New and highly efficient accelerated stress tests are able to cover the complex and multifold loading situation in the field. New analytics techniques can identify the typical failure modes and their physical root causes; (ii) Virtual techniques: Schemes of validated simulations allow capturing the physics of failure (PoF) proactively in the design for reliability (DfR) process; and (iii) Prognostics health management (PHM). A new concept is introduced for adding a minimum of PHM features at various levels of automotive electronics to provide functional safety as required for autonomous vehicles. This way, the new generation of reliability methods will continuously provide estimates of the remaining useful life (RUL) for each relevant part under the actual use conditions to allow triggering maintenance in time


2001 ◽  
Author(s):  
G. P. Tandon ◽  
R. Y. Kim

Abstract A study is conducted to examine and predict the micromechanical failure modes in a unidirectional composite when subjected to tensile loading parallel to the fibers. Experimental observations are made at some selected stress levels to identify the initiation and growth of micro damage during loading. The axisymmetric damage model of a concentric cylinder is then utilized to postulate and analyze some failure scenarios.


Author(s):  
Anusha Krishna Murthy ◽  
Saikath Bhattacharya ◽  
Lance Fiondella

Most reliability models assume that components and systems experience one failure mode. Several systems such as hardware, however, are prone to more than one mode of failure. Past two-failure mode research derives equations to maximize reliability or minimize cost by identifying the optimal number of components. However, many if not all of these equations are derived from models that make the simplifying assumption that components fail in a statistically independent manner. In this paper, models to assess the impact of correlation on two-failure mode system reliability and cost are developed and corresponding expressions for reliability and cost optimal designs derived. Our illustrations demonstrate that, despite correlation, the approach identifies reliability and cost optimal designs.


2020 ◽  
Author(s):  
Bradley Scott Henderson

The meniscus is a wedge-shaped fibrocartilaginous tissue located between the femur and tibia that helps stabilize the knee and protect the underlying cartilage. There are 2.5 million reported knee injuries each year, making it the most injured joint in the human body. Nearly twenty percent of these injuries are due to a torn meniscus, leading to over half a million meniscus surgeries performed in the United States annually. Therefore, it is critical to understand the failure modes of meniscus tissue to prevent these debilitating injuries. A failure mode that accounts for one-third of all meniscus injuries is repeated exposure to low-magnitude tensile loads, known as fatigue. One approach to gain physical insight into fatigue mechanisms is through cyclic tensile experiments performed in laboratories. An alternative approach is to use constitutive mathematical models that predict and describe the material's behavior. These models can avoid the expense and time required for experimental fatigue studies, but they also must be calibrated and validated using experimental data. The aim of this study is to validate a constitutive model to predict human meniscus' observed fatigue behavior in force-controlled loading. Three variations of constitutive models were applied to test each model's ability to model fatigue induced creep. These models included a viscoelastic damage model, a continuum damage mechanics model, and a viscoelastic model. Using a custom program, each models' parameters were fit to stretch-time plots from previously performed fatigue experiments of cadaveric human meniscus. The quality of fit for each model was then measured. The results of this study show that a viscoelastic damage formulation can effectively fit force-controlled fatigue behavior and, on average, performed the best of the three models presented. On average, the resulting NRMSE values for stretch at all creep stages were 0.22%, 2.03%, and 0.45% for the visco-damage, damage-only, and visco-only models, respectively. The requirement of including both viscoelasticity and damage to model all three creep stages indicates that viscoelasticity may be the driving factor for damage accumulation in fatigue loading. Further, the relatively low damage values, ranging from 0.05 to 0.2, right before exponential increases in stretch, indicate that failure may occur from fatigue loading without a considerable accumulation of damage. The validation results showed that the model could not completely represent pull to failure experiments when using material parameters that curve fit fatigue experiments. Still, they indicated that the combination of discontinuous CDM and viscoelasticity shows potential to model both fatigue and static loadings using a single formulation. To our knowledge, this is the first study to model force-controlled fatigue induced creep in the meniscus or any other soft tissue. This study's results can be utilized to further model force-controlled fatigue to predict and prevent meniscus tissue injuries.


2021 ◽  
Author(s):  
Michael John Stephens ◽  
Simon John Roberts ◽  
Derek James Bennet

Abstract Understanding the structural limits of subsea connectors used in offshore environments is critical to ensure safe operations. The latest industry standards establish the requirement for physical testing to validate analysis methodologies for connector designs. In this paper, an analysis methodology, compliant with the latest API 17G standard, is presented for calculating structural capacities of non-preloaded connectors. The methodology has been developed for complex combined loading scenarios and validated using full-scale physical testing for different connector families. Detailed 3-D, non-linear, finite element models were developed for three different non-preloaded connections, which consisted of threaded and load shoulder connectors. A comprehensive set of combined tension and bending moment structural capacities at normal, extreme and survival conditions were calculated for each connection. The calculated capacities were validated for each connection by performing a test sequence using full-scale structural testing. A final tension or bending to failure test was also completed for each test connection to validate the physical failure mode, exceeding the latest API 17G requirements. For all connections tested, capacities calculated using the methodology were validated from the successful completion of the test sequences. The physical failure modes of the test connections also matched the predicted failure modes from the FEA, and the tensile or bending moment loading at physical collapse exceeded that predicted by the global collapse of the FEA model. Using the validated approach described in this paper significantly reduces the requirement of physical testing for connector families, establishing confidence in the structural limits that are critical for safe operations.


2021 ◽  
Author(s):  
Barry Stewart ◽  
Sam Kwok Lun Lee

Abstract Wellhead connectors form a critical part of subsea tree production systems. Their location in the riser load path means that they are subjected to high levels of bending and tension loading in addition to internal pressure and cyclic loading. As more fields continue to be discovered and developed that are defined as High Pressure and/or High Temperature (HPHT) these loading conditions become even more arduous. In order to ensure the integrity of HPHT components, industry requirements for components are setout in API 17TR8. This technical report provides a design verification methodology for HPHT products and some requirements for validation testing. The methodology provides detail on the assessment of static structural and cyclic capacities but less detail on how to assess the functional and serviceability criteria for wellhead connectors. Similarly, API 17TR8 does not include prescriptive validation requirements for wellhead connectors and refers back to historical methods. This paper describes a practical application of the API 17TR8 methodology to the development of a 20k HPHT connector and how it was implemented to verify and validate the connector design through full scale tests to failure. A methodology was developed to meet the requirements of the relevant industry standards and applied to the connector to develop capacity charts for static combined loading. Verification was carried out on three dimensional 180° FEA models to ensure all non axi-symmetric loading is accurately captured. Connector capacities are defined based on API 17TR8 criteria with elastic plastic analysis (i.e. collapse load, local failure and ratcheting), functionality/serviceability criteria defined through a FMECA review and also including API STD 17G criteria including failure modes such as lock/unlock functionality, fracture based failure, mechanical disengagement, leakage and preload exceedance. These capacities are validated through full scale testing based on the requirements of API 17TR7 and API STD 17G with combined loading applied to the Normal, Extreme and Survival capacity curves (as defined by "as-built" FEA using actual material properties). Various test parameters such as strain gauge data, hub separation data, displacements, etc. were recorded and correlated to FEA prediction to prove the validity of the methodology. Further validation was carried out by applying a combined load up to the FEA predicted failure to confirm the design margins of the connector. Post-test review was carried out to review the suitability of the requirements set out in API 17TR8 and API STD 17G for the verification and validation of subsea connectors. The results build on previous test results to validate the effectiveness of the API 17TR8 code for verification and validation of connectors. The results show that real margins between failure of the connector and rated loads are higher than those defined in API 17TR8 and show that the methodology can be conservative.


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