Umer Sharif

Fracture Toughness Analysis of Aluminium Foil and its Adhesion with LDPE for Packaging Industry

The purpose for this thesis is to investigate the mechanical properties of the aluminium foil use... more The purpose for this thesis is to investigate the mechanical properties of the aluminium foil used for packaging industry, the reaction of the material exposed to loading and the crack sensitivity coupled to the maximum strain in the material after loading. This investigation will be based on both physical experiments and numerical simulations in the Finite Element Method program ABAQUS for with and without initial crack of different length. The simulations purpose is to get a better understanding of the different material parameters and the physical tests serves to verify the numerical model and to prove its credibility. The final model in ABAQUS will be used to test the parameters in an extensive parameter study with the ambition to find an ultimate combination of the parameters both for the material and its adhesion with LDPE.

format_quoteThe critical stresses for aluminium foil with varying crack lengths were modeled, showing strong correlation between theoretical and experimental results.format_quote

Download

Comparative Analysis of Cutting Forces, Torques, and Vibration in Drilling of Bovine, Porcine, and Artificial Femur Bone with Considerations for Robot Effector Stiffness

Journal of Healthcare Engineering, Oct 19, 2020

Bone drilling is known as one of the most sensitive milling processes in biomedical engineering f... more Bone drilling is known as one of the most sensitive milling processes in biomedical engineering field. Fracture behavior of this cortical bone during drilling has attracted the attention of many researchers; however, there are still impending concerns such as necrosis, tool breakage, and microcracks due to high cutting forces, torques, and high vibration while drilling. is paper presents a comparative analysis of the cutting forces, torques, and vibration resulted on different bone samples (bovine, porcine, and artificial femur) using a 6dof Robot arm effector with considerations of its stiffness effects. Experiments were conducted on two spindle speeds of 1000 and 1500 rpm with a drill bit diameter of 2.5 mm and 6 mm depth of cut. e results obtained from the specimens were processed and analyzed using MATLAB R2015b and Visio 2000 software; these results were then compared with a prior test using manual and conventional drilling methods. e results obtained show that there is a significant drop in the average values of maximum drilling force for all the bone specimens when the spindle speed changes from 1000 rev/min to 1500 rev/min, with a drop from (20.07 to 12.34 N), approximately 23.85% for bovine, (11.25 to 8.14 N) with 16.03% for porcine, and (5.62 to 3.86 N) with 33.99% for artificial femur. e maximum average values of torque also decrease from 41.2 to 24.2 N•mm (bovine), 37.0 to 21.6 N•mm (porcine), and 13.6 to 6.7 N•mm (artificial femur), respectively. At an increase in the spindle speed, the vibration amplitude on all the bone samples also increases considerably. e variation in drilling force, torque, and vibration in our result also confirm that the stiffness of the robot effector joint has negative effect on the bone precision during drilling process.

format_quoteMaximum cutting forces decreased from 20.07 N to 12.34 N by increasing spindle speed from 1000 to 1500 rpm across bone specimens.format_quote

Download

Experimental Investigation of Relationship between Cutting Force, Vibration Frequency and Temperature Gradient During Robotic Assisted Bone Drilling

Bone drilling processes are often carried out in numerous surgical areas in all operational theat... more Bone drilling processes are often carried out in numerous surgical areas in all operational theatre room in various hospitals across the world, these processes includes orthopedic surgeries, which is mending and fixing of broken bones. Bone drilling is classed as one of the most sensitive milling processes in biomedical engineering field. One of the most critical problems encountered during bone drilling is high cutting force which causes an increase in temperature rise more than the tolerable limit. Optimum concentration is also needed, in order to avoid extended cracks due to high vibration which could also cause more damage to the surrounding tissues, experimental results showed that it is better to keep bone external temperature below 50°C, if exceeded, the bone could be exposed to serious damage called thermal osteonecrosis which can result to loose of bone implant interface. Previous studies are only limited to investigate the relationship between the cutting force and tempera...

Vibration Reduction, Characterization of Drill bit and Femur Bone to Forces During Robotic-Assisted Drilling Using Model Soft Fixture Embedded with Pressurized-Air Damper

Safety and precision are highly crucial in orthopedic drilling operations, therefore, the study o... more Safety and precision are highly crucial in orthopedic drilling operations, therefore, the study of vibration resistance is essential. Proper clamping of fractured bone may be difficult during surgical drilling since bone is surrounded by soft tissues, hence, to prevent this, a model clamping system embedded with regulated pressurized air balloon which serves as a damper was developed. Laser vibration sensor was attached to measure the reduced permissible signal resulted from the drilling at varying effector drill speeds. The finite element analysis of the vibration characteristics of both the drill and femur bone to deformation, stress and strain was obtained using ANSYS software. This proposed method will enhance the safety as well as reduce high possibility of complications due to uncontrolled cutting forces that cause extreme vibration during surgical drilling of bone.

Performance Analysis of Width and Thickness Tapered Geometries on Electrical Power Harvested from a Unimorph Piezoelectric Cantilever Beam

2020 IEEE 3rd International Conference on Electronics Technology (ICET), May 1, 2020

This paper presents a comparative study of a thickness tapered beam (TTB) and width tapered beam ... more This paper presents a comparative study of a thickness tapered beam (TTB) and width tapered beam (WTB) harvesters for potential vibration-based energy harvesting applications. Prior to the power output analysis, mathematical models are developed to evaluate strain distribution of the two configurations for proper implementation as substrates for unimorph harvester designs. The derived models were validated in commercial finite element analysis (FEA) software, COMSOL Multiphysics, at different dimension ratios. In addition, vibration analysis was conducted to evaluate and compare the Eigen frequency and mode shape of the geometries when coupled with piezoelectric material namely, Lead Zirconate Titanate (PZT-5H). The theoretical studies show that beam truncated in thickness direction exhibits about 18% lower resonant frequency and 6.4% (μW) higher power output than width tapered harvester with equal mass and large output impedance, respectively.

Nonlinear dynamic analysis of a reciprocative magnetic coupling on performance of piezoelectric energy harvester interfaced with DC circuit

Mechanics of Advanced Materials and Structures, Aug 2, 2021

Evaluation of Health Risk Level of Hand-Arm and Whole-Body Vibrations on the Technical Operators and Equipment in a Tobacco-Producing Company in Nigeria

Journal of Healthcare Engineering, Dec 23, 2019

Vibration is experienced when a body is subjected to either internal or external forces which cau... more Vibration is experienced when a body is subjected to either internal or external forces which cause oscillation, with most operators of industrial equipment often exposed to high dosage, higher than the stipulated values. In this research, Digital Real-Time Frequency Analyzer (RSA 5106A) was used, while the results obtained were evaluated and compared with the health guidelines of the ISO 2631-1 : 1997 and ISO 2631-5 : 2004 standards, as described in the Health Guidance Caution Zone for a daily exposure action value (EAV) of 0.47 m/s 2 and a daily exposure limit value (ELV) of 0.93 m/s. High acceleration was mostly seen on the z-axis in all the results obtained, whereas many were not within the HGCZ (A rms <0.47, and >0.93 m/s 2). Comparing (VDV <8.5 m/s 1.75 and >17 m/s 1.75) with the ISO standard, the accelerations on all x-and y-axes were slightly within the HGCZ, with just a little below 0.47 m/s 2 limit. e results obtained clearly showed that urgent action is needed virtually on all the equipment in both the Secondary Manufacturing Department (SMD) and Primary Manufacturing Department (PMD) to minimize vibration exposure on the technical operators.

Download

Damping and Stiffness Analysis of Sandwich Beam with 3D-Printed Honeycomb Core Filled with Magnetorheological Elastomer (MRE): An Experimental Approach

Polymers

The current study focuses on the production and experimental examination of sandwich beams consis... more The current study focuses on the production and experimental examination of sandwich beams consisting of an aluminum face sheet and 3D-printed honeycomb cores that are filled with magnetorheological elastomer (MRE). These cores are loaded with different ratios of (75/25)% and (50/50)% elastomer and magnetic particles, measured by weight. In order to ascertain the dynamic characteristics of sandwich beams, the constructed specimens were subjected to classic shock (free vibration) experiments, and these experiments were conducted under two conditions: with and without the application of a changing magnetic field at the free end and center of the beam. The results of the experiments suggest that the attenuation of the damping ratio exhibited satisfactory performance, particularly with respect to the structures that were being examined. The sandwich beam constructions proposed exhibited the ability to alter the damping ratio, damping coefficient, and stiffness through the application of...

format_quoteApplying magnetic fields (0 to 7.5 × 10^3 G) altered damping ratios significantly, with maximum increases observed at optimal MRE concentrations.format_quote

Download

Numerical and experimental study of a gauge-shaped beam for improved performance of piezoelectric energy harvester

Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems, May 17, 2021

This paper examines a new, non-conventional, gauge-shaped beam (GSB) cantilever for enhanced vibr... more This paper examines a new, non-conventional, gauge-shaped beam (GSB) cantilever for enhanced vibration energy scavenging. The stress evolution of the GSB as well as its eigenfrequency and energy harvesting capability (when coupled with macro fiber composite (MFC) transducer) are investigated by finite element method. A comparison of performance between the proposed GSB cantilever configuration and conventional harvester of equal mass is also conducted. Both the simulation and experimental validation results showed that the gauge-shaped beam cantilever configuration has lower resonant frequencies and improved power output when used as harvester substrate. Further, we evaluated the effect of tip mass orientation/position on the GSB harvester performance by considering five different configurations namely, Confg A, Confg B, Confg C, Confg D and Confg E. The analysis shows that Confg A with $$5 \times 20 \times 5\,{\text{mm}}^{3}$$ tipmass dimension has the highest effect of 9.8% on the output power of the harvester compared to the other configurations. However, Confg C and D have the lowest resonant frequencies at fundamental vibration mode.

Design of a vibration damping robot and force evaluation in intraoperative robotic‐assisted femoral shaft repair using a modified soft damper

The International Journal of Medical Robotics and Computer Assisted Surgery, 2021

BackgroundClosed intra‐medullary nailing fixation is a method for treating fractured femurs with ... more BackgroundClosed intra‐medullary nailing fixation is a method for treating fractured femurs with minimal invasiveness. However, this method lacks safety and precision. To avert prevailing problems such as extended cracks in the already broken bone, the design of a vibration damping robot and force evaluation system is essential.MethodsThis paper presents a sensor‐based clamping robot system embedded with a regulated pressurised air balloon. Drilling forces were monitored by a force sensor attached to the end robot effector, while the reduced vibration result was measured by a non‐contact laser displacement sensor. A 2 degree‐of‐freedom (2DOF) model was developed.ResultsForce and vibration data were obtained using a data acquisition module (EMS 309) and analysed using MATLAB software (Version R2015b). The results obtained show that both the frequencies and amplitudes of the vibration is reduced at 6 bar with effector's spindle speed of 1500 rpm.ConclusionsThis proposed concept sh...

Sandwich structures with tapered tubes as core: A quasi-static investigation

Defence Technology

On geometrical configurations of vibration-driven piezoelectric energy harvesters for optimum energy transduction: A critical review

Mechanics of Advanced Materials and Structures, Feb 4, 2022

On geometrical configurations of vibration-driven piezoelectric energy harvesters for optimum energy transduction: A critical review

Mechanics of Advanced Materials and Structures, 2022

Vibration Reduction, Characterization of Drill bit and Femur Bone to Forces During Robotic-Assisted Drilling Using Model Soft Fixture Embedded with Pressurized-Air Damper

2019 International Conference on Intelligent Informatics and Biomedical Sciences (ICIIBMS)

Safety and precision are highly crucial in orthopedic drilling operations, therefore, the study o... more Safety and precision are highly crucial in orthopedic drilling operations, therefore, the study of vibration resistance is essential. Proper clamping of fractured bone may be difficult during surgical drilling since bone is surrounded by soft tissues, hence, to prevent this, a model clamping system embedded with regulated pressurized air balloon which serves as a damper was developed. Laser vibration sensor was attached to measure the reduced permissible signal resulted from the drilling at varying effector drill speeds. The finite element analysis of the vibration characteristics of both the drill and femur bone to deformation, stress and strain was obtained using ANSYS software. This proposed method will enhance the safety as well as reduce high possibility of complications due to uncontrolled cutting forces that cause extreme vibration during surgical drilling of bone.

Nonlinear dynamic analysis of a reciprocative magnetic coupling on performance of piezoelectric energy harvester interfaced with DC circuit

Mechanics of Advanced Materials and Structures, 2021

Optimal strain-deflection analyses of a wedge edged beam for enhanced vibration energy scavenging in patch-like harvester

Mechanics Based Design of Structures and Machines, 2021

Static and Modal Analysis of Sandwich Beam Structure with Magnetorheological Honeycomb Core

2020 6th International Conference on Mechanical Engineering and Automation Science (ICMEAS), 2020

In this article a sandwich beam structure with honeycomb core filled of MRE (magnetorheological e... more In this article a sandwich beam structure with honeycomb core filled of MRE (magnetorheological elastomer) with different ratios of Elastomer and iron particles modeled in ANSYS is proposed. The simulation (resonance frequency, total deformation, equivalent stress and equivalent strain) results for structures with PLA (Polylactic acid) and ABS (Acrylonitrile butadiene styrene) honeycomb core were analyzed and compared for two different cases. The results showed that the resonance frequency of the structure decreased as the ratio of iron particles was increased for all the cases, this is due to the increase in stiffness of the structure due to higher ratio of iron particles. Secondly structure with ABS honeycomb core showed lower frequency and higher deformation than the structure with PLA honeycomb core.

Experimental Investigation of Relationship between Cutting Force, Vibration Frequency and Temperature Gradient During Robotic Assisted Bone Drilling

2020 IEEE 7th International Conference on Industrial Engineering and Applications (ICIEA), 2020

Bone drilling processes are often carried out in numerous surgical areas in all operational theat... more Bone drilling processes are often carried out in numerous surgical areas in all operational theatre room in various hospitals across the world, these processes includes orthopedic surgeries, which is mending and fixing of broken bones. Bone drilling is classed as one of the most sensitive milling processes in biomedical engineering field. One of the most critical problems encountered during bone drilling is high cutting force which causes an increase in temperature rise more than the tolerable limit. Optimum concentration is also needed, in order to avoid extended cracks due to high vibration which could also cause more damage to the surrounding tissues, experimental results showed that it is better to keep bone external temperature below 50°C, if exceeded, the bone could be exposed to serious damage called thermal osteonecrosis which can result to loose of bone implant interface. Previous studies are only limited to investigate the relationship between the cutting force and tempera...

Fracture Toughness Analysis of Aluminium Foil and its Adhesion with LDPE for Packaging Industry

The purpose for this thesis is to investigate the mechanical properties of the aluminum foil used... more The purpose for this thesis is to investigate the mechanical properties of the aluminum foil used for packaging industry, the reaction of the material exposed to loading and the crack sensitivity coupled to the maximum strain in the material after loading. This investigation will be based on both physical experiments and numerical simulations in the Finite Element Method program ABAQUS for with and without initial crack of different length. The simulations purpose is to get a better understanding of the different material parameters and the physical tests serves to verify the numerical model and to prove its credibility. The final model in ABAQUS will be used to test the parameters in an extensive parameter study with the ambition to find an ultimate combination of the parameters both for the material and its adhesion with LDPE.

format_quoteTheoretical stress calculations for aluminium foil with varying crack lengths (5, 10, 15, 20, 45 mm) show strong correlation with experimental results.format_quote

Download

Dynamic Behavior of Sandwich Structures with Magnetorheological Elastomer: A Review

Materials, 2021

Magnetorheological (MR) materials are classified as smart materials that can alter their rheologi... more Magnetorheological (MR) materials are classified as smart materials that can alter their rheological features once exposed to peripheral magnetic fields. MR materials have been a standard and one of the primary smart materials for the last few decades due to their outstanding vibration control performance in adaptive sandwich structures and systems. This paper reviews the vibration suppression investigations of flexible constructions using MR elastomers (MREs). In relations of field-dependent controllability, physical features such as stiffness and the damping of different geometrical structures integrated with the core layer of MREs are explored. The veracity of the knowledge is discussed in this article, whereby sandwich structures with different MR treatment configurations are analyzed for free and forced vibration, MRE sandwich structures are analyzed for stability under different working conditions, and the optimal positions of fully and partially treated MRE sandwich structure...

Download

Uploads

Papers by Umer Sharif

Log In