Now showing 1 - 10 of 12
  • Publication
    Finite element modelling of thin intermetallic compound layer fractures
    ( 2017)
    Ooi Eang Pang
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    ; ; ;
    Mohd Shukry Abd Majid
    A thin intermetallic compound (IMC) of solder ball joint induces strong stress concentration between the pad and solder where a crack propagated near the IMC layer. The fracture mechanism of the IMC layer is complex due to the effect of IMC thickness, crack length, solder thickness and Young’s Modulus. At present, there is still an undefined exact geometrical model correlation for numerical simulations of IMC layer fracture. Thus, this paper aims to determine the accuracy of IMC layer models subjected to crack-to-width length ratio (a/W) in correlation with the ASTM E399-83 Srawley compact specimen model using finite element (FE) analysis. Several FE models with different geometrical configurations have been proposed under 10 MPa tensile loading. In this study, the two dimensional linear elastic displacement extrapolation method (DEM) is formulated to calculate the stress intensity factor (SIF) at the crack tip. The study showed that with an error of 0.58% to 0.59%, a width of 2.1 mm and a height of 1.47 mm can be recommended as the best geometrical model for IMC layer fracture modelling which provides a wider range for a/W from 0.45 to 0.85 instead of from 0.45 to 0.55. This result is significant as it presents a method for determining fracture parameters at thin IMC layers with a combination of singular elements with meshes at different densities which is tailored to the Srawley model.
  • Publication
    Finite element modelling of thin intermetallic compound layer fractures
    A thin intermetallic compound (IMC) of solder ball joint induces strong stress concentration between the pad and solder where a crack propagated near the IMC layer. The fracture mechanism of the IMC layer is complex due to the effect of IMC thickness, crack length, solder thickness and Young’s Modulus. At present, there is still an undefined exact geometrical model correlation for numerical simulations of IMC layer fracture. Thus, this paper aims to determine the accuracy of IMC layer models subjected to crack-to-width length ratio (a/W) in correlation with the ASTM E399-83 Srawley compact specimen model using finite element (FE) analysis. Several FE models with different geometrical configurations have been proposed under 10 MPa tensile loading. In this study, the two dimensional linear elastic displacement extrapolation method (DEM) is formulated to calculate the stress intensity factor (SIF) at the crack tip. The study showed that with an error of 0.58% to 0.59%, a width of 2.1 mm and a height of 1.47 mm can be recommended as the best geometrical model for IMC layer fracture modelling which provides a wider range for a/W from 0.45 to 0.85 instead of from 0.45 to 0.55. This result is significant as it presents a method for determining fracture parameters at thin IMC layers with a combination of singular elements with meshes at different densities which is tailored to the Srawley model.
  • Publication
    Comparison on the rigid and flexible model of attitude maneuvering of a simple multi-body satellite
    ( 2014-12)
    Teoh Vil Cherd
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    ;
    Norhizam Hamzah
    ;
    Sazali Yaacob
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    ;
    Rakhmad Arief Siregar
    Rigid body assumption of a satellite model has been a common practice in spacecraft attitude manoeuvring. However, with the increasing demand for greater functionality of space activities, requires bigger and wider solar panels to cater the power needs. In this paper, simple rigid and flexible multi-body satellite model is derived using basic Newton’s second law and Assumed Mode Method. The response from both model are then simulated using MATLAB software while comparison is done to illustrate the significance of the flexible behaviour that inherited in the satellite system. With the negligence of flexible interference in the rigid model, it is likely to execute an exact attitude motion while the flexible model would yield a harmonic motion that is due to the vibratory motion of the solar panels.
  • Publication
    The Effect of Surface Inclination to Knee Joint Contact Force: A Pilot Study
    ( 2021-01-01)
    Noor Arifah Azwani Abdul Yamin
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    ;
    Ahmad Faizal Salleh
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    ;
    Compressive loading at knee during walking on slope can caused the initiation and progression of osteoarthritis due to cartilage degeneration impacted which may require long periods of medical treatment and costly. The purpose of this pilot study is to analyzed the effect of surface inclination to joint contact force at knee in frontal, sagittal and transverse plane during walking. The differences in joint contact forces obtained were analyzed using Freebody 2.0 software. The findings of this pilot study indicate that, both flat and inclined walking have almost similar trends of joint contact force at knee for each direction compared to decline walking. However, each walking condition show different magnitude of tibiofemoral joint contact force. In conclusion, the result of this pilot study could not be taken as a whole. Advancement on surface angle and number of subjects is as well as research in other joint of lower limb is recommended for future work to further understand and prevent any common injury risk during walking on inclined surface.
  • Publication
    A Review of Surgical Bone Drilling and Drill Bit Heat Generation for Implantation
    This study aims to summarize the current state of scientific knowledge on factors that contribute to heat generation during the bone drilling process and how these aspects can be better understood and avoided in the future through new research methodologies. Frictional pressures, mechanical trauma, and surgical methods can cause thermal damage and significant micro-fracturing, which can impede bone recovery. According to current trends in the technical growth of the dental and orthopedic industries’ 4.0 revaluation, enhancing drill bit design is one of the most feasible and cost-effective alternatives. In recent years, research on drilling bones has become important to reduce bone tissue damage, such as osteonecrosis (ON), and other problems that can happen during surgery. Reviewing the influence of feed rate, drill design, drill fatigue, drill speed, and force applied during osteotomies, all of which contribute to heat generation, was a major focus of this article. This comprehensive review can aid medical surgeons and drill bit makers in comprehending the recent improvements through optimization strategies for reducing or limiting thermal damage in bone drilling procedures used in the dental and orthopedic industries.
  • Publication
    Drill Bit Design and Its Effect on Temperature Distribution and Osteonecrosis During Implant Site Preparation: An Experimental Approach
    In this study, the drilling parameters will be evaluated to obtain optimal parameters in minimizing the impact of drilling damage on synthetic bone blocks. The effect of damage observed in the study is osteonecrosis that occurs in the drill hole for implant site preparation, where a smaller value is desired. The drilling parameters are optimized using the Taguchi method with two control factors: the feed rate and spindle speed; each parameter is designed in five levels. This experiment was then carried out on four different designs of drill bits, i.e., Twist (118°and 135°), spherical, and conical drill bits. While experimental planning uses L25 orthogonal arrays, the "smaller is better" approach is used as a standard analysis. The main findings of this research are 118° point angle twist drill bit is the ideal type of drill bit for bone drilling, as it produces less heat than other types of drill bits. The optimal range of feed rate and drilling speed for bone drilling is 40-60 mm/rev and 1000-1400 RPM, respectively. Combining these parameters helps to minimize heat generation during implant site preparation drilling.
  • Publication
    Temperature measurement methods in an experimental setup during bone drilling: A brief review on the comparison of thermocouple and infrared thermography
    Predicting thermal response in orthopedic surgery or dental implantation remains a significant challenge. This study aims to find an effective approach for measuring temperature elevation during a bone drilling experiment by analyzing the existing methods. Traditionally thermocouple has frequently been used to predict the bone temperature in the drilling process. However, several experimental studies demonstrate that the invasive method using thermocouple is impractical in medical conditions and preferred the thermal infrared (IR) camera as a non-invasive method. This work proposes a simplified experimental model that uses the thermocouple to determine temperature rise coupled with the thermal image source approach. Furthermore, our new method provides a significant opportunity to calibrate the thermal IR camera by finding out the undetected heat elevation in a workpiece depth.
  • Publication
    A review of factors influencing peri-implant bone loss
    Dental implants report high survival rate for the treatment of patients with missing teeth and being one of the undeniable restoration techniques. However, peri-implant bone loss has recently arisen to be the highlight in contemporary implant therapy. Therefore, the possible causes that are detrimental to dental implants and surrounding tissues are important to be discovered. The present review focuses on the current etiologies of peri-implant bone loss and subsequent complications observed in clinical practices. A comprehensive literature search was conducted via PubMed, Scopus, and ScienceDirect databases using the related keywords. The literature reveals numerous etiological factors may initiate the loss of marginal bone in dental implant application: loading protocols, implant body placement, implant macro-design features, implant surface roughness, implantation site preparation, foreign body reaction, implant material particles detachment and contamination, and oral habit. Albeit the biomechanical, biological, or combination of factors are known to contribute in marginal bone resorption, the predictability of treatment modalities to handle the defect remains controversial and unclear. Further clinical trials and sophisticated quantitative assessment would be advantageous to help scrutinize the issue.
  • Publication
    Quantifying the Impact of Drilling Parameters on Temperature Elevation within Bone during the Process of Implant Site Preparation
    ( 2024-04-01)
    Islam M.A.
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    Kamarrudin N.S.
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    ; ; ;
    Noor S.N.F.M.
    This study aimed to elucidate the influences of several drilling parameters on bone temperature during drilling, as excessive heat generation can cause thermal bone damage and affect post-surgery recovery. In vitro drilling tests were conducted on bovine femoral shaft cortical bone specimens. The parameters considered included tool rotational speed (s), feed rate (f), tool diameter (d), and drill tip angles of 118° and 135°. Drilling temperatures were studied across a range of 800–2000 rpm rotational speeds, 20–40 mm/min feed rates, and 2–4 mm drill diameters. A predictive statistical model was constructed using the response surface methodology (RSM). Analysis of variance (ANOVA) at a 95% confidence level (α = 0.05) revealed that rotational speed significantly impacted temperature increase, contributing to 59.74% of observed temperature rises. Drill diameter accounted for 16.21% of temperature variations, while feed rate contributed to 10.04% of the temperature rises. The study provides valuable insights into the predominant factors affecting bone temperature during drilling. Understanding these parameters and their interplay is pivotal for optimizing drilling conditions and minimizing potential thermal damage to bones.
  • Publication
    Parametric investigation on different bone densities to avoid thermal necrosis during bone drilling process
    ( 2021-10-25)
    Islam M.A.
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    ;
    Suhaimi M.F.F.
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    ; ;
    Mat F.
    Bone drilling is a universal surgical procedure commonly used for internal fracture fixation, implant placement, or reconstructive surgery in orthopedics and dentistry. The increased temperature during such treatment increases the risk of thermal penetration of the bone, which may delay healing or compromise the fixation's integrity. Thus, avoiding penetration during bone drilling is critical to ensuring the implant's stability, which needs surgical drills with an optimized design. Bovine femur and mandible bones are chosen as the work material since human bones are not available, and they are the closest animal bone to human bone in terms of properties. In the present study, the Taguchi fractional factorial approach was used to determine the best design of surgical drills by comparing the drilling properties (i.e., signal-to-noise ratio and temperature rise). The control factors (spindle speed, drill bit diameter, drill site depth, and their levels) were arranged in an L9 orthogonal array. Drilling experiments were done using nine experimental drills with three repetitions. The findings of this study indicate that the ideal values of the surgical drill's three parameters combination (S1D1Di2) and their percentage contribution are dependent on the drilling levels of the parameters. However, the result shows that the spindle speed has the highest temperature effect among other parameters in both (femur and mandible) bones.