scholarly journals Longitudinal Monostatic Acoustic Effective Bulk Modulus and Effective Density Evaluation of Underground Soil Quality: A Numerical Approach

2020 ◽  
Vol 11 (1) ◽  
pp. 146
Author(s):  
Yuqi Jin ◽  
Tae-Youl Choi ◽  
Arup Neogi
Keyword(s):  
Bulk Modulus ◽  
Material Properties ◽  
Numerical Approach ◽  
Layered Material ◽  
Effective Density ◽  
Effective Bulk Modulus ◽  
Fluid Environment ◽  
Density Evaluation ◽  
Novel Method ◽  
Air Void

In this study, we introduce a novel method using longitudinal sound to detect underground soil voids to inspect underwater bed property in terms of effective bulk modulus and effective density of the material properties. The model was simulated in terms of layered material within a monostatic detection configuration. The numerical model demonstrates the feasibility of detecting an underground air void with a spatial resolution of about 0.5 λ and can differentiate a soil firmness of about 5%. The proposed technique can overcome limitations imposed by conventional techniques that use spacing-consuming sonar devices and suffer from low penetration depth and leakage of the transverse sound wave propagating in an underground fluid environment.

A Simple Approach to Characterize Finite Compressibility of Elastomers

2003 ◽  
Vol 76 (4) ◽  
pp. 912-922 ◽  
Author(s):  
Mark R. Gurvich ◽  
Thomas S. Fleischman
Keyword(s):  
Carbon Black ◽  
Bulk Modulus ◽  
Experimental Verification ◽  
Material Properties ◽  
Numerical Approach ◽  
Simple Approach ◽  
Experimental Measurements ◽  
Axially Loaded ◽  
Different Levels

Abstract A hybrid experimental-numerical approach is proposed for accurate dimensionless characterization of rubber finite compressibility. Rubber specimens in the form of bonded rubber disks are considered as elastomeric structures with unknown material properties. These properties are calculated by matching results of FEA with experimental measurements of radial deformations of the axially-loaded disks. The approach may be used for reliable characterization of Poisson's ratio, bulk modulus, or other characteristics of interest. Implementation of the approach is considered for two representative elastomeric compounds with different levels of carbon black. Good experimental verification of the approach is shown at different levels of loading. Moreover, the same parameters of finite compressibility are independently obtained using both compressive and tensile loads. Higher compressibility is observed for a compound with larger content of carbon black as expected.

Modeling and Experimental Validation of the Effective Bulk Modulus of a Mixture of Hydraulic Oil and Air

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Hossein Gholizadeh ◽  
Doug Bitner ◽  
Richard Burton ◽  
Greg Schoenau
Keyword(s):  
Experimental Data ◽  
Bulk Modulus ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Air Bubbles ◽  
Pressure Sensitivity ◽  
Hydraulic Oil ◽  
Effective Bulk Modulus ◽  
Experimental Apparatus ◽  
Major Factors

It is well known that the presence of entrained air bubbles in hydraulic oil can significantly reduce the effective bulk modulus of hydraulic oil. The effective bulk modulus of a mixture of oil and air as pressure changes is considerably different than when the oil and air are not mixed. Theoretical models have been proposed in the literature to simulate the pressure sensitivity of the effective bulk modulus of this mixture. However, limited amounts of experimental data are available to prove the validity of the models under various operating conditions. The major factors that affect pressure sensitivity of the effective bulk modulus of the mixture are the amount of air bubbles, their size and the distribution, and rate of compression of the mixture. An experimental apparatus was designed to investigate the effect of these variables on the effective bulk modulus of the mixture. The experimental results were compared with existing theoretical models, and it was found that the theoretical models only matched the experimental data under specific conditions. The purpose of this paper is to specify the conditions in which the current theoretical models can be used to represent the real behavior of the pressure sensitivity of the effective bulk modulus of the mixture. Additionally, a new theoretical model is proposed for situations where the current models fail to truly represent the experimental data.

Optimal Bounds on the Effective Bulk Modulus of Polycrystals

1989 ◽  
Vol 49 (3) ◽  
pp. 824-837 ◽  
Author(s):  
Marco Avellaneda ◽  
Graeme W. Milton
Keyword(s):  
Bulk Modulus ◽  
Effective Bulk Modulus ◽  
Optimal Bounds

A Novel Method to Fabricate a Molecular Quantum Structure: Selective Growth of C60on Layered Material Heterostructures

1999 ◽  
Vol 38 (Part 1, No. 1B) ◽  
pp. 511-514 ◽  
Author(s):  
Keiji Ueno ◽  
Kentaro Sasaki ◽  
Koichiro Saiki ◽  
Atsushi Koma
Keyword(s):  
Layered Material ◽  
Selective Growth ◽  
Quantum Structure ◽  
Novel Method

scholarly journals Effect of material properties on optimal radial strain gage locations in sharp V-notched configurations

2018 ◽  
Vol 172 ◽  
pp. 03002 ◽  
Author(s):  
Pranjol Paul ◽  
K.S.R. Krishna Murthy ◽  
Debabrata Chakraborty
Keyword(s):  
Strain Gage ◽  
Material Properties ◽  
A Priori ◽  
Radial Strain ◽  
Numerical Approach ◽  
Conference Paper ◽  
Notch Angle ◽  
Notch Stress ◽  
Notch Length

A simple yet reliable and powerful methodology using only one strain gage has been recommended for appropriate determination of notch stress intensity factor (NSIF) for sharp V-notched configurations subjected to mode I condition. The methodology is supported by strong theoretical postulates, and it permits the gage to be pasted prominently apart from tip of the notch thus avoiding various problems associated with singularities. Unlike the conventional methodologies, the recommended strain gage methodology also proposes optimal radial strain gage locations which are beneficial in appropriate determination of NSIFs. A FEM based numerical approach is adopted for obtaining optimal radial gage locations a priori for the aforesaid configuration. The optimal radial gage locations are observed to be influenced by parameters viz. the notch angle, the ratio of notch length to width of the plate and also material properties. Results were already published by the authors to establish that the optimal radial gage locations are influenced by the notch angle and the ratio of notch length to width of the plate. In this conference paper, a case is studied with a completely different material to check whether material properties influence the graphical trends of results or not.

A Novel Non-Destructive Method for Measuring Elastic Moduli of Cultivated Cartilage Tissues

2007 ◽  
Vol 342-343 ◽  
pp. 853-856 ◽  
Author(s):  
Duk Young Jung ◽  
Yu Bong Kang ◽  
Toshie Tsuchiya ◽  
Sadami Tsutsumi
Keyword(s):  
Mechanical Properties ◽  
Bulk Modulus ◽  
Soft Tissues ◽  
Articular Chondrocytes ◽  
Collagen Gel ◽  
Accuracy And Precision ◽  
Novel Method ◽  
Silicone Rubbers ◽  
High Degree ◽  
Non Destructive

Accurate measurement of the mechanical properties of artificial or cultivated cartilage is a major factor for determining successive regeneration of defective soft tissues. In this study, we developed a novel method that enabled the bulk modulus (k-modulus) to be measured nondestructively using the relationship between volume and pressure of living soft tissues. In order to validate this method we estimated the bulk modulus of soft silicone rubbers using our new method and a conventional method. The results showed a 5 ~ 10% difference between the results obtained with the two methods. Our method was used subsequently to measure the mechanical properties of cultivated cartilage samples (collagen gel type), that had been incubated for four weeks in the presence or absence of human articular chondrocytes (HACs). Our experiments showed that cultivated cartilage tissues grown in the presence of HACs had a higher bulk modulus (120 ± 20 kPa) than samples grown without HACs (90 ± 15 kPa). The results indicated that our novel method offered an effective method for measurement of volume changes in minute living soft tissues, with the measurements having a high degree of accuracy and precision. Furthermore, this method has significant advantages over conventional approaches as it can be used to rapidly and accurately evaluate the strength of soft tissues during cultivation without causing damage to the specimen.

Aerodynamic Flutter and Flight Surface Actuation

2007 ◽  
Author(s):  
S. A. Gadsden ◽  
S. Habibi
Keyword(s):  
Bulk Modulus ◽  
Small Amplitude ◽  
Mechanical Load ◽  
Impedance Control ◽  
Hydraulic Oil ◽  
Effective Bulk Modulus ◽  
Two Parameters

This paper proposes a novel form of impedance control in order to reduce the effects of aerodynamic flutter on a flight surface actuator. The forces generated by small amplitude flutter were studied on an electrohydrostatic actuator (EHA). The effects of flutter were modeled and analyzed. Through analysis, it was found that in EHA systems, two parameters would impact the response of flutter: damping (B) of the mechanical load, and the effective bulk modulus of the hydraulic oil (βe). These can be actively controlled as proposed here in order to provide variable impedance. The results of changing these variables are discussed and presented here.

scholarly journals Tensile Fracture Mechanism of Masonry Wallettes Parallel to Bed Joints: A Stochastic Discontinuum Analysis

Modelling ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 78-93
Author(s):  
Bora Pulatsu ◽  
Semih Gonen ◽  
Ece Erdogmus ◽  
Paulo B. Lourenço ◽  
Jose V. Lemos ◽  
...  
Keyword(s):  
Material Properties ◽  
Fracture Mechanism ◽  
Equations Of Motion ◽  
Constitutive Models ◽  
Numerical Approach ◽  
Tensile Fracture ◽  
Fracture Mechanisms ◽  
Contact Points ◽  
Statistical Variations ◽  
Modeling Strategy

Nonhomogeneous material characteristics of masonry lead to complex fracture mechanisms, which require substantial analysis regarding the influence of masonry constituents. In this context, this study presents a discontinuum modeling strategy, based on the discrete element method, developed to investigate the tensile fracture mechanism of masonry wallettes parallel to the bed joints considering the inherent variation in the material properties. The applied numerical approach utilizes polyhedral blocks to represent masonry and integrate the equations of motion explicitly to compute nodal velocities for each block in the system. The mechanical interaction between the adjacent blocks is computed at the active contact points, where the contact stresses are calculated and updated based on the implemented contact constitutive models. In this research, different fracture mechanisms of masonry wallettes under tension are explored developing at the unit–mortar interface and/or within the units. The contact properties are determined based on certain statistical variations. Emphasis is given to the influence of the material properties on the fracture mechanism and capacity of the masonry assemblages. The results of the analysis reveal and quantify the importance of the contact properties for unit and unit–mortar interfaces (e.g., tensile strength, cohesion, and friction coefficient) in terms of capacity and corresponding fracture mechanism for masonry wallettes.

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