Notice of RetractionShear response of a clamped beam subjected to intense dynamic loading with considering weakening effect of the shear sliding cross-section
The present paper, adopting a rigid, perfectly plastic idealization material model and a square yield locus, with the consideration of two conditions of weakening and non-weakening effects of transverse shear sliding section, analyses the shear response of a clamped beam in the initial plastic deformation stage subject to a uniformly distributed impulsive loading and the precondition of possible shear failure mode, writes the shear's movement equation, puts forward the expressions of shear velocity and shear sliding volume, finally the conclusion of the availability of different shear response model for weakening effect is drawn.
Shear Failure of a Free-Free Beam Subjected to Impact by a Projectile at the Mid-Span
Shear failure is an important mode of dynamic failure of structural members under impulsive loading.In this paper the non-dimensional criterion of the shear failure of a free-free beam subjected to impact by a projectile at the mid-span is presented.It is illustrated that whether a shear failure occurs at the interface,where the initial velocity has discontinuity,depends on the initial kinetic energy of the projectile,the mass ratio and the non-dimensional thickness of the beam.
Hedy: A Gradual Language for Programming Education
One of the aspects of programming that learners often struggle with is the syntax of programming languages: remembering the right commands to use and combining those into a working program. Prior research demonstrated that students submit source code with syntax errors in 73% of cases and even the best students do so in 50% of cases. An analysis of 37 million compilations by 250.000 students found that the most common error was a syntax error, which occurred in almost 800.000 compilations. It was also found that Java and Perl are not easier to understand than a programming language with randomly generated keywords, stressing the difficulties that novices face in understanding syntax. This paper presents Hedy: a new way of teaching the syntax of a programming language to novices, inspired by educational methods by which punctuation is taught to children. Hedy starts as a simple programming language without any syntactic elements such as brackets, colons or indentation. The rules slowly and gradually change until the novices are programming in Python. Hedy is evaluated on 9714 programs.