scholarly journals Design, Analysis and Experiment of the Fiber Push-Out Device Based on Piezoelectric Actuator

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1420
Author(s):  
Mengxin Sun ◽  
Yong Feng ◽  
Jiangtao Xu ◽  
Xiaoyu Wang ◽  
Haojie Zhou
Keyword(s):  
Mechanical Properties ◽  
Theoretical Analysis ◽  
Piezoelectric Actuator ◽  
Structural Parameters ◽  
Failure Process ◽  
Interfacial Shear Stress ◽  
Interfacial Shear ◽  
Flexible Beam ◽  
Maximum Displacement ◽  
Push Out

In this study, a fiber push-out device based on a piezoelectric actuator was designed, analyzed and tested, and its experimental environment was designed. The piezoelectric actuator includes a flexible beam. By using response surface analysis (RSM), taking the large displacement as the objective function and on the premise of meeting the strength requirements, the structural parameters of the flexible beam were analyzed. In the process of fiber push-out, the interfacial shear stress was estimated by establishing the system integrating the fiber-matrix-composite three-phase model and the piezoelectric actuator model using the analytic method, and the theoretical analysis results of the fiber interface mechanical properties were given. A prototype of the system was made, and the performance tests of the piezoelectric actuator and the fiber push-out device were carried out. The test results showed that the designed piezoelectric actuator can achieve a stepping resolution of 6.67 μm and a maximum displacement of about 100 μm at the input voltage of 150 V, which is consistent with the design results. The extrusion test of a single fiber was carried out using a piezoelectric actuator. The mechanical properties of the interfacial layer during the push-out process were measured and the interfacial shear strength was calculated, which is consistent with the theoretical analysis results. Finally, based on the mechanical properties obtained from the test, the loading failure process of the fiber was simulated by finite element analysis, which well explained the failure process of the fiber, thus verifying the feasibility of the designed fiber push-out device.

An Analytical Model to Predict the Push-Out Capacity of Mortar from Rock Block

2011 ◽  
Vol 250-253 ◽  
pp. 2396-2406
Author(s):  
Shu Tong Yang
Keyword(s):  
Analytical Model ◽  
Interfacial Shear Stress ◽  
Tensile Load ◽  
Interfacial Shear ◽  
Rock Block ◽  
Ground Anchors ◽  
Proposed Model ◽  
Wide Range ◽  
Rock Interface ◽  
Push Out

Ground anchors have been very practical in a wide range of geotechnical structures. Good bond properties at the anchor-mortar and mortar-rock interfaces can ensure transmitting an applied tensile load to a load bearing structure efficiently. The bond performance between the mortar and rock is necessary to be studied. A push-out test of mortar from rock block can be used to analyze the interfacial properties between the two materials. In this paper, an analytical model is proposed to determine the push-out capacity of mortar from rock block. Based on the deformation compatibility at the interface, the compressive stress in the mortar and the interfacial shear stress at the mortar-rock interface are formulated at different loading stages. By modeling interfacial debonding as an interfacial shear crack, the push-out load is then expressed as a function of the interfacial crack length. In virtue of the Lagrange Multiplier Method, the maximum push-out load is determined. The validity of the proposed model is verified with the experimental results. It can be concluded that if the interfacial parameters at the mortar-rock interface are obtained, the push-out capacity of mortar from rock block can be accurately determined using the proposed model. The proposed solution in this paper would provide a good theoretical basis in evaluating the stability of ground anchors in practice.

Evaluating Mechanical Properties of Hard Coatings by Using Relativity Method

2006 ◽  
Vol 313 ◽  
pp. 53-58
Author(s):  
Yi Wang Bao ◽  
V.T. Bublik ◽  
Jow Lay Huang ◽  
R.H. Sung
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Maximum Stress ◽  
Interfacial Shear Stress ◽  
Interfacial Shear ◽  
Hard Coatings ◽  
Coated Sample ◽  
Properties Of Coatings ◽  
Strain Mode ◽  
Absolute Value

Mechanical properties of coatings are usually affected by the substrate behavior and the thickness of the coating. The film on a substrate can’t be tested like a monolithic sample. Therefore, the absolute value of the mechanical properties of the film is often difficult to obtain, but the properties of a coated sample and a monolithic sample could be measured, and there must be a unique relation between them. Based on this consideration, a relativity method was proposed to evaluate the mechanical properties of coatings, including the hardness, elastic modulus. Satisfactory results have been obtained from the experiments using this clue. Moreover, residual stresses caused by mismatch of the coefficients of thermal expansion between the coating and substrate was calculated based on the uneven strain mode, it indicates that the interfacial shear stress concentrated at edges and maximum stress in coating is at the center.

scholarly journals Effect of a Bio-Based Dispersing Aid (Einar® 101) on PLA-Arbocel® Biocomposites: Evaluation of the Interfacial Shear Stress on the Final Mechanical Properties

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1549
Author(s):  
Laura Aliotta ◽  
Vito Gigante ◽  
Patrizia Cinelli ◽  
Maria-Beatrice Coltelli ◽  
Andrea Lazzeri
Keyword(s):  
Mechanical Properties ◽  
Shear Stress ◽  
Quantitative Estimation ◽  
Interfacial Shear Stress ◽  
Impact Resistance ◽  
Cellulose Fibers ◽  
Interfacial Shear ◽  
Analytical Models ◽  
Poly Lactic Acid ◽  
The Matrix

In this paper, the production and the characterization of poly (lactic) acid (PLA)-based composites containing different amounts (from 10 wt.% to 25 wt.%) of ultra-short cellulose fibers (Arbocel 600 BE/PU) have been investigated. On the basis of a previous study, it was observed that the addition of the cellulose fibers led to an embrittlement of the composite. Consequently, in order to obtain a composite with enhanced impact resistance and elongation at break, the effect of the Einar 101 addition (a bio-based dispersing aid additive) was analyzed. The role of the adhesion between the fiber and the matrix, coupled with a better fiber dispersion, was thus evaluated. Also, the consequences on the final mechanical properties (tensile and impact test) caused by the Einar addition were investigated. Analytical models were also applied in order to obtain an evaluation of the variation of the interfacial shear stress (IFSS) (strictly correlated to the fiber-matrix adhesion) caused by the Einar introduction. Furthermore, due to the very low aspect ratio of the Arbocel fibers, a suitable Bader and Boyer model variation was adopted in order to have a better quantitative estimation of the IFSS value.

Strength Evaluation of Unidirectional Composites Using Monte-Carlo Simulation

2014 ◽  
Vol 518 ◽  
pp. 184-189 ◽  
Author(s):  
Qiu Mei Wang ◽  
Lei Tan ◽  
Zheng Qin Liu
Keyword(s):  
Experimental Data ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Failure Process ◽  
Interfacial Shear Stress ◽  
Strength Distribution ◽  
Interfacial Shear ◽  
Shear Lag ◽  
Distribution Parameters ◽  
Pp Composites

A statistics method was carried out to characterize the fatigue strength distribution of GF/PP composites. Based on the stress of yarn bundles, the Weibull distribution parameters were determined. Also, we had presented an expression of interfacial shear stress between yarn tows and matrix. A Monte-Carlo simulation with 2D shear-lag equation had been used to analyze the tensile strength and simulate the failure process of unidirectional stretch of composites. Good agreements were obtained between the predicted results and experimental data.

scholarly journals Engineering large, anatomically shaped osteochondral constructs with robust interfacial shear properties

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Wendy E. Brown ◽  
Brian J. Huang ◽  
Jerry C. Hu ◽  
Kyriacos A. Athanasiou
Keyword(s):  
Mechanical Properties ◽  
Interfacial Shear Strength ◽  
Femoral Condyle ◽  
Interfacial Shear ◽  
Cartilage Defects ◽  
Porous Hydroxyapatite ◽  
Cartilage Lesions ◽  
Large Cartilage Lesions ◽  
Articular Cartilage Defects ◽  
Shape And Size

AbstractDespite the prevalence of large (>5 cm2) articular cartilage defects involving underlying bone, current tissue-engineered therapies only address small defects. Tissue-engineered, anatomically shaped, native-like implants may address the need for off-the-shelf, tissue-repairing therapies for large cartilage lesions. This study fabricated an osteochondral construct of translationally relevant geometry with robust functional properties. Scaffold-free, self-assembled neocartilage served as the chondral phase, and porous hydroxyapatite served as the osseous phase of the osteochondral constructs. Constructs in the shape and size of an ovine femoral condyle (31 × 14 mm) were assembled at day 4 (early) or day 10 (late) of neocartilage maturation. Early osteochondral assembly increased the interfacial interdigitation depth by 244%, interdigitation frequency by 438%, interfacial shear modulus by 243-fold, and ultimate interfacial shear strength by 4.9-fold, compared to late assembly. Toward the development of a bioprosthesis for the repair of cartilage lesions encompassing up to an entire condylar surface, this study generated a large, anatomically shaped osteochondral construct with robust interfacial mechanical properties and native-like neocartilage interdigitation.

Changes of Selected Structural and Mechanical Properties of the Strzelin Granites As Induced By Thermal Loads / Wpływ Obciążeń Termicznych Na Zmiany Niektórych Strukturalnych I Mechanicznych Właściwości Granitów Strzelińskich

2012 ◽  
Vol 57 (4) ◽  
pp. 951-974 ◽  
Author(s):  
Andrzej Nowakowski ◽  
Mariusz Młynarczuk
Keyword(s):  
Mechanical Properties ◽  
Nuclear Waste ◽  
Structural Changes ◽  
Structural Parameters ◽  
Total Porosity ◽  
Fracture Network ◽  
Qualitative Description ◽  
Temperature Changes ◽  
Heating And Cooling ◽  
Waste Repositories

Abstract Temperature is one of the basic factors influencing physical and structural properties of rocks. A quantitative and qualitative description of this influence becomes essential in underground construction and, in particular, in the construction of various underground storage facilities, including nuclear waste repositories. The present paper discusses the effects of temperature changes on selected mechanical and structural parameters of the Strzelin granites. Its authors focused on analyzing the changes of granite properties that accompany rapid temperature changes, for temperatures lower than 573ºC, which is the value at which the β - α phase transition in quartz occurs. Some of the criteria for selecting the temperature range were the results of measurements carried out at nuclear waste repositories. It was demonstrated that, as a result of the adopted procedure of heating and cooling of samples, the examined rock starts to reveal measurable structural changes, which, in turn, induces vital changes of its selected mechanical properties. In particular, it was shown that one of the quantities describing the structure of the rock - namely, the fracture network - grew significantly. As a consequence, vital changes could be observed in the following physical quantities characterizing the rock: primary wave velocity (vp), permeability coefficient (k), total porosity (n) and fracture porosity (η), limit of compressive strength (Rσ1) and the accompanying deformation (Rε1), Young’s modulus (E), and Poisson’s ratio (ν).

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