Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Peridynamics (4)
- Brittle fracture (2)
- Crack branching (2)
- Dynamic fracture (2)
- Nonlocal methods (2)
-
- Continuum mechanics (1)
- Crack nucleation (1)
- CubeSat (1)
- Elasticity (1)
- Fracture (1)
- Isogeometric analysis (1)
- J-integral (1)
- Material stability (1)
- Mechanical design (1)
- Meshfree methods (1)
- NURBS (1)
- Nonlinear (1)
- Nonlocal models (1)
- Open Orbiter Project (1)
- Open hardware (1)
- Path-independence (1)
- Peridynamic (1)
- Rotation-free (1)
- Shells (1)
- Small Spacecraft (1)
- Small spacecraft (1)
- Spacecraft structure (1)
- File Type
Articles 1 - 6 of 6
Full-Text Articles in Mechanical Engineering
The Formulation And Computation Of The Nonlocal J-Integral In Bond-Based Peridynamics, Wenke Hu, Youn Doh Ha, Florin Bobaru, Stewart A. Silling
The Formulation And Computation Of The Nonlocal J-Integral In Bond-Based Peridynamics, Wenke Hu, Youn Doh Ha, Florin Bobaru, Stewart A. Silling
Florin Bobaru Ph.D.
This work presents a rigorous derivation for the formulation of the J-integral in bond-based peridynamics using the crack infinitesimal virtual extension approach. We give a detailed description of an algorithm for computing this nonlocal version of the J-integral.We present convergence studies (m-convergence and δ-convergence) for two different geometries: a single edge-notch configuration and a double edge-notch sample.We compare the results with results based on the classical J-integral and obtained from FEM calculations that employ special elements near the crack tip.We identify the size of the nonlocal region for which the peridynamic J-integral value is near the classical FEM solutions.We discuss …
The Meaning, Selection, And Use Of The Peridynamic Horizon And Its Relation To Crack Branching In Brittle Materials, Florin Bobaru, Wenke Hu
The Meaning, Selection, And Use Of The Peridynamic Horizon And Its Relation To Crack Branching In Brittle Materials, Florin Bobaru, Wenke Hu
Florin Bobaru Ph.D.
This note discusses the peridynamic horizon (the nonlocal region around a material point), its role, and practical use in modeling. The objective is to eliminate some misunderstandings and misconceptions regarding the peridynamic horizon. An example of crack branching in a nominally brittle material (homalite) is addressed and we show that crack branching takes place without wave interaction. We explain under what conditions the crack propagation speed depends on the horizon size and the role of incident stress waves on this speed.
Crack Nucleation In A Peridynamic Solid, S. Silling, O. Weckner, E. Askari, Florin Bobaru
Crack Nucleation In A Peridynamic Solid, S. Silling, O. Weckner, E. Askari, Florin Bobaru
Florin Bobaru Ph.D.
A condition for the emergence of a discontinuity in an elastic peridynamic body is proposed, resulting in a material stability condition for crack nucleation. The condition is derived by determining whether a small discontinuity in displacement, superposed on a possibly large deformation, grows over time. Stability is shown to be determined by the sign of the eigenvalues of a tensor field that depends only on the linearized material properties. This condition for nucleation of a discontinuity in displacement can be interpreted in terms of the dynamic stability of plane waves with very short wavelength. A numerical example illustrates that cracks …
Studies Of Dynamic Crack Propagation And Crack Branching With Peridynamics, Youn Doh Ha Ph.D., Florin Bobaru Ph.D.
Studies Of Dynamic Crack Propagation And Crack Branching With Peridynamics, Youn Doh Ha Ph.D., Florin Bobaru Ph.D.
Florin Bobaru Ph.D.
In this paper we discuss the peridynamic analysis of dynamic crack branching in brittle materials and show results of convergence studies under uniform grid refinement (m-convergence) and under decreasing the peridynamic horizon (δ-convergence). Comparisons with experimentally obtained values are made for the crack-tip propagation speed with three different peridynamic horizons.We also analyze the influence of the particular shape of themicro-modulus function and of different materials (Duran 50 glass and soda-lime glass) on the crack propagation behavior. We show that the peridynamic solution for this problem captures all the main features, observed experimentally, of dynamic crack propagation and branching, as well …
Work To-Date On Mechanical Design For An Open Hardware Spacecraft, Jacob Brewer, Brian Badders, Josh Berk, Jeremy Straub
Work To-Date On Mechanical Design For An Open Hardware Spacecraft, Jacob Brewer, Brian Badders, Josh Berk, Jeremy Straub
Jeremy Straub
The OpenOrbiter CubeSat seeks to demonstrate the designs created for the Open Prototype for Educational NanoSats (OPEN) initiative. OPEN provides a set of freely available design documents that can be utilized by educational and research teams worldwide. The OPEN structure implements a different strategy than most other CubeSats, allowing it to maximize the use of the overhang space (an area of space between the supports for the frame rails and the wall in the PPOD deployer). It also provides a location for payload components or a propellant tank at the spacecraft’s center of mass. This design is enabled by a …
Blended Isogeometric Shells, D. J. Benson, S. Hartmann, Y. Bazilevs, Ming-Chen Hsu, T.J.R. Hughes
Blended Isogeometric Shells, D. J. Benson, S. Hartmann, Y. Bazilevs, Ming-Chen Hsu, T.J.R. Hughes
Ming-Chen Hsu
We propose a new isogeometric shell formulation that blends Kirchhoff–Love theory with Reissner–Mindlin theory. This enables us to reduce the size of equation systems by eliminating rotational degrees of freedom while simultaneously providing a general and effective treatment of kinematic constraints engendered by shell intersections, folds, boundary conditions, the merging of NURBS patches, etc. We illustrate the blended theory’s performance on a series of test problems.