Biomechanics Measurements in Archery

The purpose of this study is to measure the biomechanics parameters of the sport of archery and correlate these with the games performance. Archery is becoming a sport that may potentially success in the 2016 Olympic Games. Therefore, research in this sport can be directly relevant to athlete’s performance during games tournaments. This research is considered as a preliminary study to measure the biomechanics parameters that can be applied to the professional athlete. Biomechanics parameters such as muscle activity, heartbeat, balance and body posture as well as the draw force line were selected as important parameters related to the athlete’s performance. The subject in this study shot arrows on a force plate while a high speed video camera captured the arrow velocity, body posture and elbow angle. Furthermore, these parameters are then correlated with the point of the target or the archer’s performance in order to propose the correct shooting technique. The findings of this study are the draw force line angle, the most active muscle, the foot weight balance and the aiming concentration release time. All the results will help both coach and athlete to improve the performance of the sport, and especially assist both beginner level archers aiming to become expert and elite players

Design of protective headgear for soccer players through experimental and computational analysis

The uniqueness of soccer is the fact that one is allowed to use the head to direct the ball in the game. This purposeful ball-to-head impact has become one of the causes of head injuries in soccer. Clinical studies have linked multiple soccer headings with the risk of sustaining mild traumatic brain injury. This study attempts to look into this matter from the engineering perspective. A human head finite element model was adopted from a previous study and validated against a published cadaveric experimental data of intracranial pressures and linear head acceleration. A good agreement was reached between the predicted head responses and those of the cadaveric experiment. The validated soccer ball and human head finite element models were assembled to perform soccer heading simulations. To validate the finite element analysis, a soccer heading experiment was conducted on human volunteers. An instrumented mouthpiece was used to record linear and angular head accelerations during the soccer heading trials. The simulation results match those of the experiment with more than 80% accuracy. Furthermore, the study aims to evaluate the efficacy of impact-absorbing foams in mitigating the risk of sustaining head injury due to soccer heading. Another soccer heading experiment was carried out with the volunteers wearing a commercial soccer headgear. The linear and angular head accelerations obtained were compared to those of without wearing the headgear. The results demonstrate that the headgear is incapable of reducing the risk of head injury. Finite element analyses of soccer heading with wearing the headgear were performed. The comparison of both results reveal a good agreement, which suggest that the finite element models developed is a useful tool in the development of a new protective headgear for soccer players. In addition, parametric studies of the foam material properties show that an elastomeric foam alone might not be able to attenuate the risk of sustaining head injury due to soccer heading

Design of a dynamometer-engine coupling shaft / Mohd Hasnun Arif Hassan

In measuring the power output of an engine, the engine has to be coupled to a load device known as dynamometer. The coupling is done by means of a solid shaft. The proper couplings and shaft are required for the connection to avoid any failure to the engine or the dynamometer. Unsuitable selection could lead to undesired problems such as torsional vibrations, vibration of the engine and dynamometer, whirling of the coupling shaft, damage of the bearings, engine starting problem or immoderate wear of the shaft line components. The commonly encountered problem is the resonance in torsional vibration, which results in disastrous failure of the shaft due to excessive vibration. This project is aimed to study the appropriate design of the shaft to be used in the dynamometer-engine coupling to prevent the system from undergoing unwanted problems. The theoretical calculations involve in the design are presented. The dimension of the coupling shafts for engines with various maximum torques are estimated. It is shown that the diameter of the shaft is proportional to the maximum torque of the engine given that the same coupling is used for every system, whereas the length of the shaft is almost equal for every engine. The diameter of the shaft is a vital parameter compared to its length. For engines with the maximum torque vary from 40 to 200 Nm, the same shaft length of 500 mm can be used but with increasing shaft diameter as the maximum torque increases. For a 40 Nm engine, the shaft diameter of 20 mm generated acceptable result. The shaft diameter was increased by 5 mm as the maximum torque increases and acceptable results were obtained. On the other hand, by using aluminium instead of steel as the material of the shaft, lower critical engine speed is obtained given that the same dimension of the shaft is used. This is due to the fact that aluminium possesses lower modulus of rigidity in comparison to steel

Finite Element Analysis of Soccer Heading

AbstractStudies have shown compelling evidence that suggests heading soccer ball might lead to brain trauma. Researchers have attempted to experimentally quantify head acceleration induced by soccer ball heading. A series of linear accelerometers as well as angular accelerometer were used to measure head accelerations. This method however is limited to measuring only head acceleration during the impact. However, it is essential to analyse the acceleration of the brain in addition to the acceleration of the head that takes place during a soccer-heading manoeuvre. Since the motion of the brain is almost impossible to be quantified experimentally, this work focuses on performing finite element (FE) analysis of soccer heading to study the motions of both the head and the brain during the impact. FE model of soccer ball was developed and validated against published experimental data as well as a more detailed model. Moreover, FE model of human head that consists of the skull, facial bones, cerebrospinal fluid (CSF) layer and the brain was also developed and validated against experimental data of blunt impact on human cadaver. Both validated models were assembled to perform the soccer heading simulations. Linear and angular accelerations of the skull and the brain generated are comparable to those of experimental data. However, it has underestimated the angular acceleration due to the absence of neck in the model, but with comparable acceleration profile. Linear and angular accelerations of the brain were found to be almost similar to those of the head, which is contradictory to our initial hypothesis. Further study such as ball impact on instrumented dummy skull is required to corroborate the findings. Nonetheless, the FE models were able to replicate the head accelerations sustained during soccer ball heading satisfactorily. The simulation results show that the models can be employed in finding protective materials that can reduce the accelerations, thus minimising the probability of suffering from long-term brain trauma due to soccer ball heading

Flipped Classroom Approach in Rigid Body Dynamics: A Case Study of Five-Semester Observation

Flipped classroom is an alternative approach to the conventional lecture by introducing collaborative tasks in the class to promote active learning. Theoretical lecture was delivered to the students through videos, which they watch at home prior to the class. The implementation of this method at undergraduate level especially in engineering courses was reported to be lacking. This study presents a five-semester observation in Rigid Body Dynamics course, during which the first two semesters were conducted using conventional approach, and the following three semesters were flipped. Three indicators were measured to evaluate the effectiveness of the method: the percentage of failures, the number of student enrolments, and the lecturer evaluation score. There is a strong evidence showing that flipped classroom has increased the student's performance. In addition, it was found that the students prefer this method compared to the conventional approach. This study demonstrates that flipped classroom can be implemented in engineering courses with a good chance of success

Technical and tactical performance indicators discriminating winning and losing team in elite Asian beach soccer tournament.

The present study aims to identify the essential technical and tactical performance indicators that could differentiate winning and losing performance in the Asian elite beach soccer competition. A set of 20 technical and tactical performance indicators namely; shot back-third, shot mid-third, shot front-third, pass back-third, pass mid-third, pass front-third, shot in box, shot outbox, chances created, interception, turnover, goals scored 1st period, goals scored 2nd period, goals scored 3rd period, goals scored extra time, tackling, fouls committed, complete save, incomplete save and passing error were observed during the beach soccer Asian Football Confederation tournament 2017 held in Malaysia. A total of 23 matches from 12 teams were notated using StatWatch application in real-time. Discriminant analysis (DA) of standard, backward as well stepwise modes were used to develop a model for the winning (WT) and losing team (LT) whilst Mann-Whitney U test was utilized to ascertain the differences between the WT and LT with respect to the performance indicators evaluated. The standard backward, forward and stepwise discriminates the WT and the LT with an excellent accuracy of 95.65%, 91.30% and 89.13%, respectively. The standard DA model discriminated the teams from seven performance indicators whilst both the backward and forward stepwise identified two performance indicators. The Mann-Whitney U test analysis indicated that the WT is statistically significant from the LT based on the performance indicators determined from the standard mode model of the DA. It was demonstrated that seven performance indicators namely; shot front-third, pass front-third, chances created, goals scores at the 1st period, goals scored at the 2nd period, goals scored at 3rd period were directly linked to a successful performance whilst the incomplete save by the keeper attribute towards the poor performance of the team. The present finding could serve useful to the coaches as well as performance analysts as a measure of profiling successful performance and enables team improvement with respect to the associated performance indicators

Forecasting road deaths in Malaysia using support vector machine

An average of 6,350 people died every year in Malaysia due to road traffic accidents. A published data of Malaysian road deaths in 20 years since 1997 reveals that the number of fatalities has not really declined with a difference of less than 10% from one year to the next. Forecasting the number of fatalities is beneficial in planning a counter measure to bring down the death toll. A predictive model of Malaysian road death has been developed using a time-series model known as auto regressive integrated moving average (ARIMA). The model was used in the previous Road Safety Plan of Malaysia to set a target death toll to be reduced in 2020, albeit being inaccurate. This study proposes a new approach in forecasting the road deaths, by means of a machine learning algorithm known as Support Vector Machine. The length of various types of road, number of registered vehicles and population were among the eight features used to develop the model. Comparison between the actual road deaths and the prediction demonstrates a good agreement, with a mean absolute percentage error of 2% and an R-squared value of 85%. The Linear kernel-based Support Vector Machine was found to be able to predict the road deaths in Malaysia with reasonable accuracy. The developed model could be used by relevant stakeholders in devising appropriate poli-cies and regulations to reduce road fatalities in Malaysia

Finite Element Analysis of Impact Energy on Spur Gear

In high-speed gear drive and power transmission, system impact failure mode always occurs due to the sudden impact and shock loading during the system in running. Therefore, study on the amount of impact energy that can be absorbed by a gear is vital. Impact test equipment has been designed and modelled for the purpose to study the impact energy on gear tooth. This paper mainly focused on Finite Element Analysis (FEA) of impact energy that occurred during simulation involving the impact test equipment modelling. The simulation was conducted using Abaqus software on critical parts of the test equipment to simulate the impact event and generate impact data for analysis. The load cell in the model was assumed to be free fall at a certain height which gives impact load to the test gear. Three different type of material for the test gear were set up in this simulation. Results from the simulation show that each material possesses different impact energy characteristic. Impact energy values increased along with the height of load drop. AISI 1040 were found to be the toughest material at 3.0m drop that could withstand up to 44.87N.m of impact energy. These data will be used to validate data in physical experiments in further study