Masniezam Ahmad
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Preferred name
Masniezam Ahmad
Official Name
Masniezam, Ahmad
Alternative Name
Ahmad, Masniezam H.
Ahmad, M.
Main Affiliation
Scopus Author ID
56272606200
Researcher ID
IXE-4791-2023

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An energy absorption characterization of improved circular thin-walled tubes under dynamic loading

2013 , Masniezam Ahmad

Thin-walled tube is one of the energy absorber devices designed to dissipate energy and increase the efficiency of a crashworthiness structure in an impact event. During an accident, thin-walled tube dissipates the kinetic energy of the structure and converts the kinetic energy into the other form of energy thus minimize the impact experienced by the occupant. This research examines the thin-walled tube subjected to axial dynamic crushing experiment by using a drop weight impact tester. A nonlinear finite element model for the tube crushing has been developed by using LS-DYNA software and a good agreement has been achieved between the finite element model and experimental results. The parametric studies of the thin-walled tubes have been performed by using the validated FE model. The analysis of energy absorption characteristics includes the energy absorption capacity, initial peak load, specific energy absorption (SEA) and crush force efficiency (CFE) results. The shape, material and geometry of the tube are varied to investigate the effect of using these parameters to the energy absorption characteristics. As a result, circular tube is capable to provide better energy absorption characteristics compared to the square tube. The tubes designed by three different materials which are aluminium alloy AA6061-T6, carbon steel S1214 and magnesium alloy AZ31B-O has been developed in LS-DYNA. It was found that the magnesium alloy AZ31B-O is highly potential to be created as the thin-walled tube material instead of aluminium alloy and carbon steel since it has excellent result in initial peak load, SEA and CFE. However, when the applications neglect the damage of the structure and does not involving human, carbon steel is the best material as it can absorb most energy capacity and high mean crushing force. The effect of length, diameter and thickness of the tube to the energy absorption characteristics has been investigated. It was concluded that initial peak load and CFE are optimum in thicker and larger tube. Energy absorption capacities are optimum in thicker, larger and longer tube while SEA result is optimum in thicker, smaller and shorter tube. At the end, the modifications performed on the original tube shows an improvement in the energy absorption characteristics compared to the current tube designs. A combination of conical tube with flat end cap was proposed as the best modified tube since it has excellent results on initial peak load, CFE and SEA with moderate results on the energy absorption capacity. Research information provided in this study will serve as a guide to design the thin-walled tube in the future.

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Turning experiment of Ti-6Al-4V by using uncoated carbide insert

2020 , Muhamad Fitri Mahazer , Muhammad Syamil Zakaria , Masniezam Ahmad , Akmal Faris Shahbani

Titanium alloy Ti-6Al-4V is widely being used in the blades, discs, rings, airframes, fasteners, components, vessels, cases, hubs, forgings and biomedical implants. Nevertheless, the properties of titanium alloys which are low thermal conductivity, low modulus of elasticity and high chemical activity cause it very difficult to machine. Excessive elevated temperature due to low thermal conductivity of these alloys make it favorable for tool wear. In this paper, an experiment using orthogonal array L4 is conducted to explore the effect of cutting parameters e.g. cutting speed, depth of cut and feed rate in terms of surface roughness and tool wear. The cutting tool uncoated carbide is used in performing orthogonal cutting of Ti-6Al-4V in this study. It is found low cutting speed, feed rate and high depth of cut is favourable in producing good Ra and minimum flank wear.

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Energy Absorption Characteristics of Thin-Walled Tubes Filled with Rice Husk and Kenaf Fibers

2024-12-02 , Masniezam Ahmad , Khairul Azwan Ismail , Fauziah Che Mat , Mohd. Hazwan Mohd. Hanid , Ahmad Azraai Abd Aziz

This study investigates the energy absorption characteristics of thin-walled tubes filled with rice husk and kenaf fibers when compressed under axial compression. The aim of this study is to evaluate the crashworthiness parameters such as energy absorption (EA), initial peak load (IPL), crush force efficiency (CFE) and specific energy absorption (SEA). Experimental results show that tubes filled with rice husk and kenaf exhibit significant improvements in overall energy absorption compared to empty tubes. However, while both fillers enhanced EA, the SEA values were lower than predicted. Thus, it is suggested that further optimization, such as adjusting filler density or exploring hybrid filler combinations, could improve crashworthiness. This study highlights the potential for rice husk and kenaf fibers as sustainable filler options for lightweight, impact-resistant designs in automotive, aerospace, and other engineering applications, with opportunities for improvement in future research.

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Energy absorption and failure behavior of Al/CFRP/GFRP hybrid tubes under quasi-static axial loading

2023-07-01 , Fauziah Che Mat , Mohd Ridzuan Mohd Jamir , Masniezam Ahmad , Mohd Shukry Abdul Majid , Khairul Azwan Ismail

Fiber metal laminate (FML) is gaining increased interest among researchers in designing thin-walled tubes as an efficient energy absorber. The combination of aluminum tube and fiber-reinforced polymer (FRP) as an FML hybrid tube has successfully demonstrated enhanced crashworthiness performance of structures. Previous studies reported FML hybrid tubes employing a single type of FRP composite material as the laminate material. Investigations on the effect of stacking sequences of multiple types of FRP composite as laminate materials are limited and mostly focused on sandwich structures. This study aims to investigate the effect of reinforcement material as a laminate layer and stacking sequences on the crashworthiness characteristics of aluminum-FRP hybrid tubes under quasi-static axial compression loading. The crashworthiness characteristics and the failure behavior of aluminum monolithic tube, aluminum-single FRP material, and aluminum-multi FRP material hybrid tubes are tested and compared. Glass FRP (GFRP) demonstrates great potential as a laminate material for aluminum tube compared with carbon FRP (CFRP). Aluminum-GFRP and aluminum-GFRP-CFRP hybrid tubes exhibit a 26.4 % and 66.9 % increase in energy absorbed, respectively, compared with the monolithic aluminum tube. The specific energy absorption and crushing force efficiency of the aluminum-GFRP-CFRP hybrid tube show minimal reductions of 4.9 % and 6.2 %, respectively. GFRP is the better choice of laminate material for aluminum tubes compared with CFRP. Multiple FRP laminates show a larger crashworthiness enhancement of FRP hybrid tubes in achieving better crashworthiness performance of the energy absorber. These findings imply that the selection and stacking sequences of laminate material are vital in tailoring the performance of the hybrid tubes toward efficient energy absorbers.

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Modification of the design of circular thin-walled tubes to enhance dynamic energy absorption characteristics: experimental and finite element analysis

2020 , Masniezam Ahmad , Khairul Azwan Ismail , Mohd. Hazwan Mohd. Hanid , Fauziah Che Mat , A M Roslan

A thin-walled tube is an energy absorber device that functions to dissipate kinetic energy into another form of energy during impact. The design of thin-walled tubes is a significant factor which affects to the energy absorption characteristics. This paper provides a comparative study between the original thin-walled tube designs and several modified tube designs that have been proposed. The main objective is to improve the energy absorption characteristics, such as energy absorption capacity, initial peak load, specific energy absorption (SEA) and crush force efficiency (CFE). Throughout this research, aluminium alloy AA6061-T6 has been used as the material for all tubes. For comparison, all of the tubes are developed with a circular shape with the same diameter, thickness and length. In addition, they are also impacted at the same kinetic energy under dynamic axial loading. Validated LS-DYNA finite element (FE) models have been used to simulate the impact of the thin-walled tubes. Compared to the original tube design, the modified tubes have improved energy absorption characteristics. A conical tube with a flat end cap was identified as the best performing tube among the modified tubes because it had the lowest initial peak load, a moderate energy absorption capacity and an excellent CFE and SEA. The findings from this study can be used as a guidance in designing thin-walled structure.

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Computational Fluid Dynamics Analysis of Varied Cross-Sectional Areas in Sleep Apnea Individuals across Diverse Situations

2024-01-01 , Wan Mohd Faizal Wan Ab Rahim , Khor Chu Yee , Mohamad Suhaimi Shahrin , Muhamad Nur Misbah , Mohd. Hazwan Mohd. Hanid , Masniezam Ahmad , Mohd Haidiezul Jamal Ab Hadi

Obstructive sleep apnea (OSA) is a common medical condition that impacts a significant portion of the population. To better understand this condition, research has been conducted on inhaling and exhaling breathing airflow parameters in patients with obstructive sleep apnea. A steady-state Reynolds-averaged Navier–Stokes (RANS) approach and an SST turbulence model have been utilized to simulate the upper airway airflow. A 3D airway model has been created using advanced software such as the Materialize Interactive Medical Image Control System (MIMICS) and ANSYS. The aim of the research was to fill this gap by conducting a detailed computational fluid dynamics (CFD) analysis to investigate the influence of cross-sectional areas on airflow characteristics during inhale and exhale breathing in OSA patients. The lack of detailed understanding of how the cross-sectional area of the airways affects OSA patients and the airflow dynamics in the upper airway is the primary problem addressed by this research. The simulations revealed that the cross-sectional area of the airway has a notable impact on velocity, Reynolds number, and turbulent kinetic energy (TKE). TKE, which measures turbulence flow in different breathing scenarios among patients, could potentially be utilized to assess the severity of obstructive sleep apnea (OSA). This research found a vital correlation between maximum pharyngeal turbulent kinetic energy (TKE) and cross-sectional areas in OSA patients, with a variance of 29.47%. Reduced cross-sectional area may result in a significant TKE rise of roughly 10.28% during inspiration and 10.18% during expiration.

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Improved models for impact of Viscoplastic bodies

2018 , Masniezam Ahmad

Impact between two bodies is a complex phenomenon commonly occurs in many areas such as sports, automotive, geology and many more. Until now, modeling an impact is still a challenging task due to inherent imprecision of constitutive laws for the impact mechanics. Previously, impulse-momentum method was used as general principle to solve this dynamic problem. Then, impact is modeled by employing a lumped-parameter, which is represented by the spring and/or dashpot elements as a compliance at a small contact region around the point of contact. Through this method, the mechanics of contact during a short interval of impact event can be calculated. Formulation of the model using elastic, viscoelastic, elastoplastic or viscoplastic constitutive material behavior is employed as a contact law for the compliance at the small deforming region. At a very low impact velocity, an elastic model based on Hertz contact theory and the viscoelastic Hunt & Crossley model have accurately predicted impact responses. However, at higher impact velocities, a significant part of the initial kinetic energy is dissipated due to plastic deformation, stress wave propagation, sound, heat and other effects. An elastoplastic impact model can be used to predict the elastic-plastic deformation of the impacted bodies, however the effect of stress wave propagation is not considered in this model. This problem has been addressed by adopting a viscoplastic model that can predict the impact response which encompasses both elastic and plastic deformation and also considers the energy dissipated due to wave propagation. This study proposes two viscoplastic impact models that were developed from modification of previous viscoplastic models; Yigit and Ismail & Stronge models. The proposed model provides an alternative method to predict the impact responses by employing a linear spring element or combining a linear and nonlinear spring element in restitution phase of the compliance. The impact responses for several types of balls have been also studied by drop test experiments and finite element analysis. In experiment, various tests have been conducted to ensure accurate measurements of force and velocity for drops of different sports balls. On the other hand, an accurate finite element model (FE model) was developed and it was validated with previous FE model. As a result, the impact responses obtained from the proposed models have been validated with both experiment and FE analysis. In general, the proposed models can predict the maximum force and contact time with percentage error of less than 20 % and 11 % respectively. The proposed model was successfully improved the accuracy of impact response prediction for normal impact between two compact bodies. For the case of elastic impact, the proposed model gives the smallest energy loss of any of these previous models. Thus, it provides good estimation of contact forces and deformations, compared to the other viscoplastic models. Besides that, the impact responses for impact of different materials, sizes and impact velocities of the body have been obtained from the FE analysis. In overall, new developments for viscoplastic impact model and impact responses for colliding bodies were presented.

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Design and Development of a Spring-Type Fixture for Manufacturing Efficiency

2025-06-10 , Mohd Uzair Mohd Rosli , Muhammad Syamil Zakaria , Masniezam Ahmad , Muhammad Syafiq Bin Bahanuddin

The development and design of a spring-type fixture play a critical role in enhancing the precision and efficiency of manufacturing processes that require repetitive assembly or testing. This research focuses on the design, and fabrication of a spring-loaded fixture aimed at improving workpiece positioning, alignment, and clamping accuracy in various industrial applications. By integrating a spring mechanism, the fixture provides adaptive flexibility, enabling consistent pressure and secure holding, thereby minimizing operator-induced errors and increasing production throughput. The study presents a detailed analysis of the fixture's mechanical design, including the selection of materials, and dimensions while maintaining cost-effectiveness. Cutting simulations are conducted using MasterCAM software to assess toolpath accuracy and detect potential collisions, optimizing the fixture’s functionality. The results demonstrate that the spring-type fixture achieves significant improvements in repeatability and precision, particularly in industries such as automotive, aerospace, and electronics. This design contributes to the advancement of fixture technology by offering a solution that enhances both operational consistency and efficiency in high-precision manufacturing environments.

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A Parametric Study on The Performance of Latent Heat Thermal Energy Storage

2025-06-10 , Muhammad Haziq Akmal bin Mohd Ridzuan , Mohamad Syafiq Abdul Khadir , Adel Nasser , Masniezam Ahmad , Mohd Haidiezul Jamal Ab Hadi , Muhamad Nur Misbah , Abdul Syafiq Abdull Sukor

Thermal energy storage (TES) systems play a crucial role in sustainable energy management by storing excess energy for later use, improving overall efficiency, reducing emissions, and enhancing grid reliability. Among TES technologies, latent heat thermal energy storage (LHTES) systems are particularly attractive due to their high energy storage capacity and ability to operate at nearly constant temperatures. However, the low thermal conductivity of phase change materials (PCMs) remains a significant challenge, limiting the rate of heat transfer and overall system performance. This study explores the performance of an LHTES system by examining the effects of inlet temperature, mass flow rate, and flow direction, with a particular focus on horizontal flow configurations. The aim is to identify optimal parameter settings that enhance heat transfer efficiency and improve system performance. Using ANSYS Fluent, numerical simulations were conducted with paraffin wax RT82 as the PCM and copper as the triplex tube heat exchanger material. The results showed that an optimized parameter combination reduced the melting time to 232.8 minutes, a 51.44% improvement over the baseline case. These findings highlight the potential for strategic parameter optimization to significantly enhance LHTES efficiency by accelerating PCM melting and improving thermal distribution. This study provides valuable insights into optimizing LHTES system performance, contributing to the development of more effective energy storage solutions that minimize energy losses and improve thermal management.

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