Authentication in Welded Clad Plate with Similar Material and Thickness

This paper continues the research previously done by authors on numerical modelling of the dissimilar welded joints with varying clad thicknesses using a commercial finite element software. The current study simulates the welding conditions of a similar clad plate with a thin thickness. The computer simulated outcome then verified with the measured data of from other researchers. A close match between the numerical models and the experimental data was found.Peer reviewedFinal Published versio

Reconstruction of a long head biceps using Bashti method; comparison between two different insertion techniques

The Long Head Biceps (LHB) is one of the most vulnerable tendons in the human body, and its damage can cause problems for the patient, such as limitation of arms ability to motion, severe pain and reducing the strength of arm. The complete tear of the LHB may need a surgical treatment. Although, the existing surgical method can reattach the tear tendon but there are demands to improve the conventional LHB reconstruction methods. Bashti Bone Plug Technique (BBPT) is an implant-less surgical technique. The method can improve the quality of LHB surgical treatment. The purpose of this study is to investigate the effect of insertion techniques on biomechanical properties of the Bashti fixation method. The study uses bovine tendons and artificial Sawbones blocks with the density of 15 pcf correlated to the density of a young human radius bone. These specimens allocated into two groups with an equal number of samples. In the first group, the insertion process was performed using a manual hammer where the impacts' frequency was uncontrolled. In the second group, the samples were inserted using an automatic hammer with a constant and controlled frequency of 3600 beats per minute (BPM). All other conditions, including geometry of the samples, were the same for all specimens in both groups. After the sample preparation, samples were tested under a poll-out test. All samples were subjected to a cyclical test followed by a single cycle load to failure test. The cyclical test performed using preconditioning to adjust the setup and a periodic load between 10 N and 70 N, for 100 cycles. The rate of loading was 500 mm per minutes. Immediately after completing the cyclical test, the samples loaded under a simple tensile loading with the same loading speed until a fixation failure. Considering the experimental outcome, for the first group, the average maximum tensile strength was 235±39.4 N and the average stiffness was 9.25±2.12 N/mm, while for the second group the average maximum tensile strength was 163±54.5 N and the average stiffness was 8.46±4.9 N/mm. The study firstly proven that Bashti reconstruction method is a suitable method to fix LHB. In addition, it was concluded that the insertion technique has a significant effect on the maximum tensile strength of the Bashti fixation method. Further study on effect of insertion frequency is ongoing. Please note this paper originally written in Farsi language. The full paper is attached.Peer reviewedFinal Accepted Versio

Influence of Conventional Shot Peening Treatment on the Service Life Improvement of Bridge Steel Piles Subjected to Sea Wave Impact

© 2023 The authors. Licensee MDPI, Basel, Switzerland. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/The first goal of the current study is to estimate the fatigue life of the middle steel piles of an integrated bridge installed in water and subject to the impact of sea waves. In the following, the authors have tried to improve the service life of this critical part of the bridge, which is also the main purpose of the study. To this end, conventional shot peening, as one of the most well-known surface treatments, was used. Axial fatigue tests were performed on samples fabricated from IPE-220 steel piles in two states without and with shot peening surface treatment. Next, the modified S-N curve was entered into the finite element software to define the effect of shot peening treatment. Different analysis, including thermal, thermal-structural coupled, and transient dynamic, were performed and various outputs were extracted for the entire structure. In all these analyses, changes in air temperature have been neglected. The most important achievement of this research is the discovery that motionless water cannot cause serious damage to steel piles. Moreover, application of conventional shot peening can increase the fatigue life of steel piles, or in other words the service life of the bridge, subjected to the impact of sea waves by about 22%.Peer reviewe

Quarter and Full Car Models Optimisation of Passive and Active Suspension System Using Genetic Algorithm

© The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/This study evaluates a suspension design of a passenger car to obtain maximum rider's comfort when the vehicle is subjected to different road profile or road surface condition. The challenge will be on finding a balance between the rider's comfort and vehicle handling to optimize design parameters. The study uses a simple passive suspension system and an active suspension model integrated with a pneumatic actuator controlled by proportional integral derivative (PID) controller in both quarter car and full car models having a different degree of freedoms (DOF) and increasing degrees of complexities. The quarter car considered as a 2-DOF model, while the full car model is a 7-DOF model. The design process set to optimise the spring stiffnesses, damping coefficients and actuator PID controller gains. For optimisation, the research featured genetic algorithm optimisation technique to obtain a balanced response of the vehicle as evaluated from the displacement, velocity and acceleration of sprung and unsprung masses along with different human comfort and vehicle performance criteria. The results revealed that the active suspension system with optimised spring stiffness, damping coefficients and PID gains demonstrated the superior riding comfort and road holding compared to a passive suspension system.Peer reviewe

Using finger for touchscreen devices; Is it safe?

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The use of touchscreen devices become a part of people daily life. Finger is used to communicate with such devices. This paper investigated the interaction between human finger and touch screen devices. A series of experiments was performed to investigate the participants' finger functionality when they press their finger on a touch screen device. The study was concluded that the pain threshold is higher than normal pressing force but for repetitive pressing the level of pain threshold will decrease.Final Accepted Versio

A Predictive Model for Assessment of Successful Outcome in Posterior Spinal Fusion Surgery

Background: Low back pain is a common problem in many people. Neurosurgeons recommend posterior spinal fusion (PSF) surgery as one of the therapeutic strategies to the patients with low back pain. Due to the high risk of this type of surgery and the critical importance of making the right decision, accurate prediction of the surgical outcome is one of the main concerns for the neurosurgeons.Methods: In this study, 12 types of multi-layer perceptron (MLP) networks and 66 radial basis function (RBF) networks as the types of artificial neural network methods and a logistic regression (LR) model created and compared to predict the satisfaction with PSF surgery as one of the most well-known spinal surgeries.Results: The most important clinical and radiologic features as twenty-seven factors for 480 patients (150 males, 330 females; mean age 52.32 ± 8.39 years) were considered as the model inputs that included: age, sex, type of disorder, duration of symptoms, job, walking distance without pain (WDP), walking distance without sensory (WDS) disorders, visual analog scale (VAS) scores, Japanese Orthopaedic Association (JOA) score, diabetes, smoking, knee pain (KP), pelvic pain (PP), osteoporosis, spinal deformity and etc. The indexes such as receiver operating characteristic–area under curve (ROC-AUC), positive predictive value, negative predictive value and accuracy calculated to determine the best model. Postsurgical satisfaction was 77.5% at 6 months follow-up. The patients divided into the training, testing, and validation data sets.Conclusion: The findings showed that the MLP model performed better in comparison with RBF and LR models for prediction of PSF surgery.Keywords: Posterior spinal fusion surgery (PSF); Prediction, Surgical satisfaction; Multi-layer perceptron (MLP); Logistic regression (LR) (PDF) A Predictive Model for Assessment of Successful Outcome in Posterior Spinal Fusion Surgery. Available from: https://www.researchgate.net/publication/325679954_A_Predictive_Model_for_Assessment_of_Successful_Outcome_in_Posterior_Spinal_Fusion_Surgery [accessed Jul 11 2019].Peer reviewe

Sheathed fixation improves BASHTI technique in an anterior cruciate ligament reconstruction

© 2023 IMechE 2023. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/Bone and Site Hold Tendon Inside (BASHTI) technique is an implant-less surgical methodology used for anterior cruciate ligament (ACL) reconstruction. It has some clinical advantages, such as speeding up the healing process. Since the force required to insert the core bone inside the tunnel may damage the core bone and affect the fixation process, the study aims to investigate the strength of fixation of BASHTI technique using proposed sheathed core bones. Experimental tests were performed to evaluate the biomechanical strength of the fixation. Synthetic bone combined with bovine tendons as a graft was used. Polymers were used to create the sheath for mechanical testing. The results showed that fixation strength and stiffness in PTFE sheath with 0.1 mm were 343.86 N and 114.62 N/mm and in PVC sheath with similar thickness, 235.95 N, and 93.36 N/mm. Subsequently, 0.2 mm PTFE sheaths were tested in two different sections: incomplete fixation and complete fixation. The strength and stiffness of the first section were 221.6 N and 66.99 N/mm and for the second section 420.02 N and 126.16 N/mm. Using sheath facilitates the fixation process in BASHTI technique. The 0.1 mm PTFE sheath and 0.2 mm PTFE sheath with complete fixation provide higher fixation strength than other groups. The outcome showed that engaged length has a direct effect on the fixation strength. The BASHTI technique offers an implant-less organic ACL reconstruction method that can improve the fixation method and speed up the healing process.Peer reviewe

A multi-objective approach to optimize the weight and stress of the locking plates using finite element modeling

© IMechE 2021. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1177/09544119211048286This paper aims to identify an optimum bone fracture stabilizer. For this purpose, three design variables including the ratio of the screw diameter to the plate width at three levels, the ratio of the plate thickness to the plate width at three levels, and the diameter of the bone at two levels were selected for analysis. Eighteen 3D verified finite element models were developed to examine the effects of these parameters on the weight, maximum displacement and maximum von Mises stress of the fixation structure. Considering the relations between the inputs and outputs using multivariate regression, a genetic algorithm was used to find the optimal choices. Results showed that the diameter of the bone and the amount of load applied on it did not have a significant effect on the normalized stresses on the structures. Furthermore, in all ratio of the plate thickness to the plate width, as the ratio of the screw diameter to the plate width increased, the amount of stress on the structure decreased. But, by further increasing the ratio of the screw diameter to the plate width, the amount of stress on the structure increased. On the other hand, by increasing the value of the ratio of the plate thickness to the plate width, the maximum amount of stress on the structure decreased. Finally, optimal solutions in terms of the weight and the maximum amount of stress on the structure were presented.Peer reviewedFinal Accepted Versio

Can the body slope of interference screw affect initial stability of reconstructed anterior cruciate ligament?: An in-vitro investigation

© The Author(s). 2021 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License. https://creativecommons.org/licenses/by/4.0/Background: Superior biomechanical performance of tapered interference screws, compared with non-tapered screws, with reference to the anterior cruciate ligament (ACL) reconstruction process, has been reported in the literature. However, the effect of tapered interference screw’s body slope on the initial stability of ACL is poorly understood. Thus, the main goal of this study was to investigate the effect of the interference screw's body slope on the initial stability of the reconstructed ACL. Methods: Based on the best screw-bone tunnel diameter ratios in non-tapered screws, two different tapered interference screws were designed and fabricated. The diameters of both screws were equal to bone tunnel diameter in one-third of their length from screw tip, then they were gradually increased by 1mm, in the lower slope (LSTIS), and 2 mm, in the higher slope (HSTIS) screws. To simulate the ACL reconstruction, sixteen soft tissue grafts were fixed, using HSTIS and LSTIS, in synthetic bone blocks. Through applying sub-failure cyclic incremental tensile load, graft-bone-screw construct's stiffness and graft laxity in each cycle, also through applying subsequent step of loading graft to the failure, maximum load to failure, and graft’s mode of failure were determined. Accordingly, the performance of the fabricated interference screws was compared with each other. Results: HSTIS provides a greater graft-bone-screw construct stiffness, and a lower graft laxity, compared to LSTIS. Moreover, transverse rupture of graft fibers for LSTIS, and necking of graft in the HSTIS group were the major types of grafts' failure. Conclusion: HSTIS better replicates the intact ACL's behavior, compared to LSTIS, by causing less damage in graft's fibers; reducing graft laxity; and increasing fixation stability. Nonetheless, finding the optimal slope remains as an unknown and can be the subject of future studies.Peer reviewedFinal Published versio

Analytical Modelling of Electromagnetic Bulging of Thin Metallic Tubes

© 2021 The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. This is the accepted manuscript version of a conference paper which has been published in final form at https://doi.org/10.1007/978-981-15-9505-9_70The main objective of this paper is to develop an analytical method based on the energy balance equation to model the plastic deformation of thin metallic tubes in a high velocity forming process under axisymmetric conditions. A yield criterion is proposed, which involves the coupled effect of the axial and circumferential internal force resultants. Using a combination of power-law strain hardening and strain rate hardening flow stress models, both strain hardening and strain rate effects are included. The proposed method permits consideration of the influence of different terms of kinetic energy and plastic work of the tube. The study presents a typical electromagnetic tube expansion model, using a dynamic high strain-rate forming method with strain-rates above 103 s−1. In this process, the deformation of the workpiece is achieved by the interaction of a current generated in the workpiece with a magnetic field generated by a coil adjacent to the workpiece. The results reveal that the achieved high strain rates influence the plastic flow stress and the final permanent radial deformation, consequently. The study concluded that an appropriate shape function eventuates a more accurate estimation of both the radial displacement and the deformed meridian profile