More Like this

1. Topologically Interlocked Material Systems: From a Material Design Concept to Properties

   Siegmund, T (September 2018, Proceedings of the IUTAM Symposium Architectured Materials Mechanics)

   Topologically interlocked stereotomic material systems are load-carrying assemblies of unit elements interacting by contact and friction. This contribution summarizes research on such material systems in a variety of configurations based on tessellation geometry and percolation, and it considers external rigid confined, external flexible confined, internal flexible confined, as well as considers the unit elements as solids (elastic and elastic-brittle) or shells (elastic), and under consideration of a range of assembly geometries. Siegmund, T. (2018). Topologically Interlocked Material Systems: From a Material Design Concept to Properties. In T. Siegmund & F. Barthelat (Eds.) Proceedings of the IUTAM Symposium Architectured Materials Mechanics, September 17-19, 2018, Chicago, IL: Purdue University Libraries Scholarly Publishing Services, 2018. https://docs.lib.purdue.edu/iutam/presentations/abstracts/70 

   more » « less
2. Causes with material continuity

   https://doi.org/10.1007/s10539-021-09826-x  

   Ross, Lauren_N (November 2021, Biology & Philosophy)

   Abstract Recent philosophical work on causation has focused on distinctions across types of causal relationships. This paper argues for another distinction that has yet to receive attention in this work. This distinction has to do with whether causal relationships have “material continuity,” which refers to the reliable movement of material from cause to effect. This paper provides an analysis of material continuity and argues that causal relationships with this feature (1) are associated with a unique explanatory perspective, (2) are studied with distinct causal investigative methods, and (3) provide different types of causal control over their effects. 

   more » « less
3. A hybrid material-point spheropolygon-element method for solid and granular material interaction

   https://doi.org/10.1002/nme.6345  

   Jiang, Yupeng; Li, Minchen; Jiang, Chenfanfu; Alonso-Marroquin, Fernando (January 2020, International Journal for Numerical Methods in Engineering)
4. Shear Wave Propagation and Estimation of Material Parameters in a Nonlinear, Fibrous Material

   https://doi.org/10.1115/1.4044504  

   Hou, Zuoxian; Okamoto, Ruth J.; Bayly, Philip V. (May 2020, Journal of Biomechanical Engineering)

   Abstract This paper describes the propagation of shear waves in a Holzapfel–Gasser–Ogden (HGO) material and investigates the potential of magnetic resonance elastography (MRE) for estimating parameters of the HGO material model from experimental data. In most MRE studies the behavior of the material is assumed to be governed by linear, isotropic elasticity or viscoelasticity. In contrast, biological tissue is often nonlinear and anisotropic with a fibrous structure. In such materials, application of a quasi-static deformation (predeformation) plays an important role in shear wave propagation. Closed form expressions for shear wave speeds in an HGO material with a single family of fibers were found in a reference (undeformed) configuration and after imposed predeformations. These analytical expressions show that shear wave speeds are affected by the parameters (μ0, k1, k2, κ) of the HGO model and by the direction and amplitude of the predeformations. Simulations of corresponding finite element (FE) models confirm the predicted influence of HGO model parameters on speeds of shear waves with specific polarization and propagation directions. Importantly, the dependence of wave speeds on the parameters of the HGO model and imposed deformations could ultimately allow the noninvasive estimation of material parameters in vivo from experimental shear wave image data. 

   more » « less
5. Systematic Evaluation of Adhesion and Fracture Toughness in Multi-Material Fused Deposition Material Extrusion

   https://doi.org/10.3390/ma17163953  

   Jafor, Md Abu; Sayah, Neshat; Smith, Douglas E; Stano, Gianni; Fleck, Trevor J (August 2024, Materials)

   Material extrusion (MEX) additive manufacturing has successfully fabricated assembly-free structures composed of different materials processed in the same manufacturing cycle. Materials with different mechanical properties can be employed for the fabrication of bio-inspired structures (i.e., stiff materials connected to soft materials), which are appealing for many fields, such as bio-medical and soft robotics. In the present paper, process parameters and 3D printing strategies are presented to improve the interfacial adhesion between carbon fiber-reinforced nylon (CFPA) and thermoplastic polyurethane (TPU), which are extruded in the same manufacturing cycle using a multi-material MEX setup. To achieve our goal, a double cantilever beam (DCB) test was used to evaluate the mode I fracture toughness. The results show that the application of a heating gun (assembled near the nozzle) provides a statistically significant increase in mean fracture toughness energy from 12.3 kJ/m2 to 33.4 kJ/m2. The underlying mechanism driving this finding was further investigated by quantifying porosity at the multi-material interface using an X-ray computed tomography (CT) system, in addition to quantifying thermal history. The results show that using both bead ironing and the hot air gun during the printing process leads to a reduction of 24% in the average void volume fraction. The findings from the DCB test and X-ray CT analysis agree well with the polymer healing theory, in which an increased thermal history led to an increased fracture toughness at the multi-material interface. Moreover, this study considers the thermal history of each printed layer to correlate the measured debonding energy with results obtained using the reptation theory. 

   more » « less