A novel noncontact indentation system with the combination of an air jet and optical coherence tomography (OCT) was presented in this paper for the quantitative measurement of the mechanical properties of soft tissues. The key idea of this method is to use a pressure-controlled air jet as an indenter to compress the soft tissue in a noncontact way and utilize the OCT signals to extract the defo...

The mechanical properties of endothelial glycocalyx were studied using atomic force microscopy with a silica bead (diameter ∼18 μm) serving as an indenter. Even at indentations of several hundred nanometers, the bead exerted very low compressive pressures on the bovine lung microvascular endothelial cell (BLMVEC) glycocalyx and allowed for an averaging of stiffness in the bead-cell contact area...

This review covers areas where our understanding of the mechanisms underlying nanoindentation has been increased by atomistic studies of the nanoindentation process. While such studies have been performed now for more than 20 years, recent investigations have demonstrated that the peculiar features of nanoplasticity generated during indentation can be analyzed in considerable detail by this tec...

This paper discusses various aspects of two ink aging methods that analyze ink volatile components, Sequential Extraction Technique (SET) and Solvent Loss Ratio Method (SLRM). Multiple ballpoint ink writings of various ages were tested by the SET and SLRM both before and after the pages bearing the writings were examined for indented writing impressions using an electrostatic detection apparatu...

Instrumented indentation methods, which provide a continuous record of the variation of indentation load, P, as a function of the depth of penetration, h, into the indented specimen, have been the topics of considerable attention in recent years. Such interest can be attributed to the following possible applications of the methods. (1) Properties such as Young’s modulus, yield strength, and str...

In this paper, the eigenfunction expansion method combined with local contact models are presented to analyze repeated impact behaviors between sphere and beam. The simulations verified experimental results of a simply-supported beam struck 91 times by sphere. order clarify validity solve transverse impacts on beams, simulation spring-mass also compared experiments. It shows that appropriate mo...

An ultrasound indentation system with a pen-size hand-held probe was developed and used to obtain the effective Young's moduli of forearm and lower limb soft tissues in 12 subjects. Since the probe is manually driven, the alignment of the probe and control of the rate of indentation are parameters upon which the results obtained depend. This paper addresses whether manual indentation tests with...

Depth-sensing indentation equipment is widely used for evaluation of the hardness and Young’s modulus of materials. The depth resolution of this technique allows the use of ultra-low loads. However, aspects related to the determination of the contact area under indentation should be cautiously considered when using this equipment. These are related to the geometrical imperfections of the tip, t...

Abstract: Focusing on incremental bulk metal forming processes, the indentation process is gaining interest as a fundamental part of these kinds of processes. This paper presents the analysis of the pressure obtained in indentation under the influence of different punch geometries. To this end, an innovative Upper Bound Theorem (UBT) based solution is introduced. This new solution can be easily...

Single-crystal sapphire (α-Al2O3) is a hard and brittle material. Due to its highly crystalline nature, the fracture behavior of sapphire is strongly related to its crystal structure, and understanding the effects of crystal structure on the crack propagation of sapphire is essential for the successful application of this important material (e.g., as wafers in the electronics industry). In the ...