Ana just sent pictures from graduation this past spring, and not a minute has been wasted generating this post (please forgive any typos).

 

Congratulations on completing your PhD, Ana!!!

 

The citation and abstract for her thesis are below, for those who may be curious about her research.  Feel free to send me (Jim) an email, and I can send you the full PDF if ProQuest does not cooperate.

 

Nally, A. (2022). Assessing optimal modes of soil parameter identification (Order No. 29166780). Available from Dissertations & Theses @ CIC Institutions; Dissertations & Theses @ Northwestern University; ProQuest Dissertations & Theses Global. (2672375859). Retrieved from http://turing.library.northwestern.edu/login

 

Abstract:  This thesis describes an exploratory project to develop a highly non-traditional approach to devise novel test methods for characterizing the properties of materials that are essential to the design of sustainable and resilient infrastructure, particularly naturally occurring materials such as soils and rocks. The central idea is that the material itself should inform the test method that most effectively reveals the material’s strength and deformability. Existing methods for inferring mechanical properties of materials through field tests or laboratory experiments have evolved largely by trial and error, and there is no general, systematic approach for evaluating one possible approach against another. Moreover, existing characterization techniques are inadequate for determining all parameters required to define the material’s behavior, particularly when the number of parameters is large. A metric to compare tests is devised by (1) creating a min-max optimization of parameter sensitivities, taking into account the local and global topological properties of the forward model, and (2) evaluating the proposed metric for fundamental material tests. Using optimization to minimize the proposed metric, the result will return the optimal material parameter test for the given constraints. The proposed metric is first implemented to simple material tests with analytical forward models before being applied to finite element analysis where more complex topology optimization can be performed. A parallel objective is included in the exploratory project, which investigates a new method to continuously discover material parameters. Prevailing techniques for on-site assessment of material parameters are capable of providing information only at specific locations—a significant shortcoming since soil parameters can vary widely over small areas. The key idea explored in this work is that opportunities for continuous characterization of ground conditions are already present in most situations, through the presence of ground-engaging equipment. The development of new techniques for discovering material parameters in this way will have a significant impact, particularly in the fields of construction and trafficability. Achievement of the objectives set out in this thesis will form the first step in enabling the discovery of new devices and testing protocols that will potentially revolutionize the way material parameters are measured.