Preliminary study of thermomechanical fatigue of polycrystalline MAR-M 200

Thermomechanical fatigue (TMF) experiments were conducted on polycrystalline MAR-M 200 over a cyclic temperature range of 500 to 1000 C. Inelastic strain ranges of 0.03 to 0.2 percent were imposed on the specimens. The TMF lives were found to be significantly shorter than isothermal low-cycle-fatigue (LCF) life at the maximum cycle temperature, and in-phase cycling was more damaging than out-of-phase cycling. Extensive crack tip oxidation appeared to play a role in promoting the severity of in-phase cycling. Carbide particle - matrix interface cracking was also observed after in-phase TMF cycling. The applicability of various life prediction models to the TMF results obtained was assessed. It was concluded that current life prediction models based on isothermal data as input must be modified to be applicable to the TMF results

Light Commercial Vehicle ADAS-Oriented Modelling: An Optimization-Based Conversion Tool from Multibody to Real-Time Vehicle Dynamics Model

In the last few years, the number of Advanced Driver Assistance Systems (ADAS) on road vehicles has been increased with the aim of dramatically reducing road accidents. Therefore, the OEMs need to integrate and test these systems, to comply with the safety regulations. To lower the development cost, instead of experimental testing, many virtual simulation scenarios need to be tested for ADAS validation. The classic multibody vehicle approach, normally used to design and optimize vehicle dynamics performance, is not always suitable to cope with these new tasks; therefore, real-time lumped-parameter vehicle models implementation becomes more and more necessary. This paper aims at providing a methodology to convert experimentally validated light commercial vehicles (LCV) multibody models (MBM) into real-time lumped-parameter models (RTM). The proposed methodology involves the definition of the vehicle subsystems and the level of complexity required to achieve a good match between the simulation results obtained from the two models. Thus, an automatic vehicle model converter will be presented together with the assessment of its accuracy. An optimization phase is included into the conversion tool, to fine-tune uncertain vehicle parameters and to compensate for inherent modelling differences. The objective function of the optimization is based on typical performance indices used for vehicle longitudinal and lateral dynamics assessment. Finally, the simulation results from the original and converted models are compared during steady-state and transient tests, to prove the conversion fidelity

Nondestructive Evaluation of Ceramic Matrix Composite Combustor Components

Combustor liners fabricated from a SiC/SiC composite (silicon carbide fibers in a silicon carbide matrix) were nondestructively interrogated before and after combustion rig testing by x-ray, ultrasonic, and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications correlated with reduced material properties obtained after rig testing. The thermography indications in the SiC/SiC liners were delaminations and damaged fiber tows, as determined through microstructural examinations

Nondestructive evaluation of ceramic matrix composite combustor components.

Combustor liners fabricated from a SiC/SiC composite were nondestructively interrogated before and after combustion rig testing. The combustor liners were inspected by X-ray, ultrasonic and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications were found to correlate with reduced material properties obtained after rig testing. Microstructural examination of the SiC/SiC liners revealed the thermography indications to be delaminations and damaged fiber tows

Emerging Adults: Parental Marital Status and Attachment on Perception of Romantic Relationships

Caroline M. Verrilli ’21, Psychology majorMargaret G. Rock ’22, Psychology and Health Policy and Management majorMia Giselle C. Binuya ’22, Psychology and Spanish majorFaculty Mentor: Dr. Jennifer Van Reet, Psycholog

Optimization of energy exchanges in utility grids with applications to residential, industrial and tertiary cases

This paper focuses on an efficient Energy Management System (EMS) developed within the European project e-Gotham. Relying on previous results on modeling and controlling microgrids operations, we propose an optimal control strategy to manage the operations of an utility grid. The goal of the proposed strategy is to minimize the operations, maintenance and generations costs balancing a time-varying power demand. The overall problem is stated as a Mixed Integer Linear Programming (MILP) problem. A Model Predictive Control (MPC) technique is used to compensate the system uncertainties. As case of study a residential, an industrial and a tertiary pilot are considered to test the proposed control strategy

Optimization of energy exchanges in utility grids with applications to residential, industrial and tertiary cases

This paper focuses on an efficient Energy Management System (EMS) developed within the European project e-Gotham. Relying on previous results on modeling and controlling microgrids operations, we propose an optimal control strategy to manage the operations of an utility grid. The goal of the proposed strategy is to minimize the operations, maintenance and generations costs balancing a time-varying power demand. The overall problem is stated as a Mixed Integer Linear Programming (MILP) problem. A Model Predictive Control (MPC) technique is used to compensate the system uncertainties. As case of study a residential, an industrial and a tertiary pilot are considered to test the proposed control strategy

Model Predictive Control for Optimization of Combined Heat and Electric Power Microgrid

This is a contribution to the economic dispatch problem of combined electrical and heat power microgrids. A mixed integer linear microgrid model has been developed; the microgrid operations optimization problem has been formulated using Mixed-Integer Linear Programming and Model Predictive Control technique has been applied to take system uncertainties into account. The proposed optimization algorithm has been applied to a tertiary site microgrid, located in Finland; the obtained numerical results have been compared with a heuristic algorithm