Network-topological formulation of analyses of geometrically and materially nonlinear space frames

Network and topological formulation of analyses of nonlinear space frame

Thermo-viscoplastic analysis of hypersonic structures subjected to severe aerodynamic heating

A thermoviscoplastic computational method for hypersonic structures is presented. The method employs unified viscoplastic constitutive model implemented in a finite element approach for quasi-static thermal-structural analysis. Applications of the approach to convectively cooled hypersonic structures illustrate the effectiveness of the approach and provide insight into the transient inelastic structural behavior at elevated temperatures

Significant elastic anisotropy in Ti1−x_{1-x}Alx_xN alloys

Strong compositional-dependent elastic properties have been observed theoretically and experimentally in Ti$_{1-x}$Al$_x$ N alloys. The elastic constant, C$_{11}$, changes by more than 50% depending on the Al-content. Increasing the Al-content weakens the average bond strength in the local octahedral arrangements resulting in a more compliant material. On the other hand, it enhances the directional (covalent) nature of the nearest neighbor bonds that results in greater elastic anisotropy and higher sound velocities. The strong dependence of the elastic properties on the Al-content offers new insight into the detailed understanding of the spinodal decomposition and age hardening in Ti$_{1-x}$Al$_x$N alloys.Comment: 3 figures, 3 page

A Priori error analyses of a stabilized discontinuous Galerkin method

AbstractWe introduce a new stabilized discontinuous Galerkin method within a new function space setting, that is closely related to the discontinuous Galerkin formulation by Oden, Babuška and Baumann [1], but involves an extra stabilization term on the jumps of the normal fluxes across the element interfaces. The formulation satisfies a local conservation property and we prove well posedness of the new formulation. A priori error estimates are derived, which are verified by 1D and 2D experiments on a reaction-diffusion type model problem

Required Counseling Provided Within a Counselor Training Program: Its Effect on Self-Awareness and the Impact of Ethical Concerns on the Experience

This study examined the experience of 140 students in a counselor training program that required students to participate in 10 sessions of individual counseling during their training program in order to increase their self-awareness. Students had the option of fulfilling the requirement through being counseled either by more advanced students within the training program or by mental health professionals outside the program. Results indicated that students in both settings reported a significant increase in their self-awareness. Students who fulfilled the requirement in a setting outside of the counseling program clinics reported a significantly higher increase in self-awareness than those who fulfilled the requirement within the counseling program clinics. Students' reports of increased self-awareness did not vary by their stages of progress through the program. Participants reported significant ethical concerns regarding confidentiality and dual relationships that reportedly reduced the beneficial impact of the counseling experience. Students who fulfilled the counseling requirement within the counseling program clinics experienced significantly greater ethical concerns than did those who fulfilled the requirement outside the program clinics. As with effect on self-awareness, stage in the program was not related to impact of ethical concerns on the required counseling experience. The overwhelming majority (91.4%) of participants supported requiring counselors in training to experience their own personal counseling. The majority of the students (58%) recommended that either a counseling program clinic or somewhere outside the program would be equally acceptable settings for future students to obtain the counseling. Of the remaining students, nearly equal numbers recommended a counseling program clinic (18%) as recommended an outside setting (24%). Potential benefits and costs to requiring individual counseling for counselors in training were examined. Advantages and disadvantages to providing the counseling within program clinics were discussed, as were various options for providing the counseling

Experimental Validation of Contact Dynamics for In-Hand Manipulation

This paper evaluates state-of-the-art contact models at predicting the motions and forces involved in simple in-hand robotic manipulations. In particular it focuses on three primitive actions --linear sliding, pivoting, and rolling-- that involve contacts between a gripper, a rigid object, and their environment. The evaluation is done through thousands of controlled experiments designed to capture the motion of object and gripper, and all contact forces and torques at 250Hz. We demonstrate that a contact modeling approach based on Coulomb's friction law and maximum energy principle is effective at reasoning about interaction to first order, but limited for making accurate predictions. We attribute the major limitations to 1) the non-uniqueness of force resolution inherent to grasps with multiple hard contacts of complex geometries, 2) unmodeled dynamics due to contact compliance, and 3) unmodeled geometries dueto manufacturing defects.Comment: International Symposium on Experimental Robotics, ISER 2016, Tokyo, Japa