UMP, HKA establish international collaboration in Dual Degree in Electrical Engineering Electronics

GERMANY, 31 May 2022 - Universiti Malaysia Pahang (UMP) signed a partnership with Hochshcule Karlsruhe (HKA) Germany to carry out the UMP-HKA Dual Degree in Electrical Engineering (Electronics) programme

UMP, HKA jalin kerjasama antarabangsa dalam Dual-Ijazah Kejuruteraan Elektrik Elektronik

JERMAN, 31 Mei 2022 - Universiti Malaysia Pahang (UMP) meterai kerjasama dengan Hochshcule Karlsruhe (HKA) Jerman bagi menjalankan program Dual-Ijazah Kejuruteraan Elektrik (Elektronik) UMP-HKA

The mechanical properties of novel lightweight structures based on corrugated-cores

The aim of this research work is to investigate the mechanical properties of corrugated-core sandwich structures under quasi-static and dynamic loading conditions and to determine the failure mechanisms and energy-absorbing characteristics of the corrugated-cores with different cell wall thickness and filled with a foam core. Triangular corrugation structures were made from an aluminium alloy (AL), a glass fibre reinforced plastic (GFRP) and a carbon fibre reinforced plastic (CFRP). The composite corrugations were fabricated using a hot press moulding technique and then adhesively bonded to skins based on the same material, to produce a range of lightweight sandwich structures. The role of the number of unit cells, the thickness of the cell walls and the width in determining the mechanical behaviour of the structures was investigated. Buckling of the struts was identified as the initial failure mode in these corrugated systems. Continued loading resulted in plastic deformation in the aluminium system, in contrast, fibre fracture, matrix cracking and localised delamination in the composite systems, as well as debonding between the skins and the core were observed in the composites. The compression strength and modulus were shown to be dependent on the number of unit cells and the cell wall thickness, but independent of specimen width. Subsequent mechanical testing was undertaken using an Arcan rig capable of generating a range of loading conditions between pure shear and pure compression. The failure strength in the aluminium system was accurately represented using a two dimensional quadratic failure criterion. In contrast, due to the initation of delamination within the composite struts, the composite corrugated-cores were accurately predicted using a modified failure criterion. Low velocity compression loading was subsequently performed on the sandwich structures, where the dynamic strength enhancement factor was shown to increase for all the corrugation systems. This was attributed to both a material strain-rate sensitivity and inertial stabilisation effects. The failure mechanisms in the sandwich structures were found to be similar under both quasi-static and dynamic loading conditions, where damage initiated due to buckling of the struts. To simulate the mechanical response of the corrugation systems, FE models have been developed using the Abaqus finite element package. The FE results were compared to measured responses, and good agreement was achieved. The failure modes predicted by the FE models show reasonably good agreement with the experimental observations. Finally, foam filling the composite corrugation systems significantly improved the specific strength as well as specific energy-absorbing characteristics of the structures. The compression properties of the corrugated structures have been compared to those of other core materials, where the evidence suggests that these systems compare favourably with other cellular core materials

Dataset of the lab-scale 3-axis winding machine integrated with the portable real-time winding angle measurement system

This article presents three datasets related to the laboratory scale 3-axis filament winding machine. The winding experimental tests are described on the range of winding angle, winding accuracy of programmed G-codes, and linear and rotation speeds in raw data. The real-time winding angle measurement system is developed to monitor and measure the winding angle of filament-wound carbon-fiber reinforced plastics (CFRP) tubes. Two winding patterns are provided as dry and wet winding processes. Moreover, an experimental test of a real-time winding angle measurement system is captured and analyzed. The i-winder app controls the winding machine through a Bluetooth module, which is programmed by MIT App Inventor. The data presented in this article can have a benchmark for developing a multi-axis filament winding machine. It is provided an inexpensive and open-source control system and is embedded in a real-time winding angle measurement system. The experimental assessment data can be found in this article [1]. The data is available in the cloud-based Mendeley Data repository [2]

Effect of hybrid FRP confinement on tin slag polymer concrete compressive strength

This study investigates the strength enhancement of Tin Slag Polymer Concrete (TSPC) under hybrid GFRP and CFRP confinement in comparison with mono GFRP and CFRP confinement on TSPC circular short column samples. Hybrid FRP confinement is prepared by wrapping TSPC with GFRP followed by CFRP both 1 layer using epoxy Sikadur 330 as matrix binders with 50 mm overlap. Compression test was performed on unconfined TSPC (TSPC-UC), TSPC with GFRP confinement (TSPC-GF), TSPC with CFRP confinement (TSPC-CF) and TSPC with hybrid FRP confinement (TSPC-HB) with 1mm/ min loading rate. The test results have revealed that the ultimate strengths are 59.19 MPa (TSPC-UC), 85.54 MPa (TSPC-GF), 108.77 MPa (TSPC-CF) and 124.59 MPa (TSPC-HB). The corresponding compressive strain measured at ultimate compressive strength is 0.0300 (TSPC-UC), 0.0453 (TSPC-GF), 0.0398 (TSPC-CF) and 0.0588 (TSPC-HB). Stress versus strain curve has shown that compared to TSPC-UC, externally strengthen sample with GFRP, CFRP and Hybrid FRP have enhanced TSPC strength with slight different behavior. TSPC-GF has less strength enhancement with larger strain while TSPC-CF provide larger strength enhancement but with lower strain. However, TSPC-HB has shown the highest strength enhancement with larger strain benefit from combined GFRP and CFRP properties. Failure mode of hybrid FRP confinement on TSPC (TSPC-HB) has shown combination of both FRP components failure mode (TSPC-GF and TSPC-CF) as in rupture pattern and delamination. The results of this study has provide findings on the effect of hybrid FRP confinement on TSPC circular column sample in close expectation based on literatures

Effect of particle discretization and horizon size on the displacement and damage plot using bond-based peridynamics

Peridynamics (PD) represents a new non-local theory of continuum mechanics which uses integro differential equations instead of the typical local partial differential equations in its formulation. Thus, it is suitable for modelling fracture mechanics, where a continuum domain is modelled through particles connected via physical interactions. The PD formulation allows us to model spontaneous crack initiation, and crack branching without the need for special mathematical treatment. The value of parameters such as particle discretization and horizon size will be chechked to make sure that it agreed to the result from FEM in elastic deformation before proceed to the failure mode. In PD, failure criterion is established when its stretch value exceeds a prescribed critical stretch value. In the classical bond model or Prototype Microelastic Brittle (PMB), the bond force grows linearly with the bond stretch, and the value suddenly goes down to zero when the bond stretch exceeds its critical value. This study will focus on the effect of horizon size and particle discretization on PD displacement of elastic analysis, and damage patterns with PMB damage model. The proposed study leads to a better understanding of how horizon size and particle disretisation affect the damage patterns in PD frameworks

A focused review of short electrospun nanofiber preparation techniques for composite reinforcement

Short nanofibers have been of interest in preparing 3D porous structures, aerosol filters, and nanocomposites. These materials require nanofiber retrieval and application in short form with simultaneous control over aspect ratio. Electrospinning, conventionally, offers minimal control over short nanofiber yield as nonwoven mat is the default configuration of collected sample. High surface area to volume ratio nanofiber, however, can offer new vistas in material design if standardization of short nanofiber preparation practices, offering control over aspect ratio, can be attained. It will provide novel insights into design of tissue engineering scaffolds, filtration membranes, and nanocomposite properties. This work summarizes reported efforts to prepare short nanofiber through mechanical, chemical, material, and operational variables. It aims to provide comparative glance at attempts to control aspect ratio along with pros and cons of the adopted techniques. Lastly, discussion shares generalized conclusions and insights gathered while reviewing material and operational variables adopted for short nanofiber preparation

Spiral wrap using CFRP strip to strengthen TSPC column under compression

This study investigates the compressive strength enhancement of TSPC column under spiral wrap orientation of CFRP strips in comparison with conventional transverse CFRP wrap on the TSPC circular column samples. The test samples were prepared by wrapping TSPC with 30 mm CFRP strip with 0.60 angular offsets from bottom and continuously wrapped until it reaches top of the TSPC column. The matrix employed was epoxy Sikadur 330-part A and B. Compression test was performed on unconfined TSPC (TSPC-UC), TSPC with transverse CFRP confinement (TSPC-CF) and TSPC with spiral CFRP strip confinement (TSPC-CS) with 1mm/ min of loading rate. The test results have revealed that the ultimate strengths are 59.19 MPa (TSPC-UC), 108.77 MPa (TSPC-CF) and 116.53 MPa (TSPC-CS). The corresponding compressive strain measured at ultimate compressive strength is 0.0300 (TSPC-UC), 0.0398 (TSPC-CF) and 0.0420 (TSPC-CS). Stress versus strain curve has shown that compared to TSPC-UC, TSPC-CF and TSPC-CS has provided strength enhancement and improvement of yield point indicate the confinement effect on the test samples. However, TSPC-CS has shown just little strength enhancement compared to TSPC-CF which reveals its incompatibility due to complexity of spiral wrap preparation process. Failure mode of TSPC-UC has shown shear crushing, TSPC-CF, delamination, and transverse fractured and TSPC-CS exhibit angular fractured. The results of this study have provided findings on the effect of spiral CFRP strip confinement on TSPC circular column sample in close expectation based on literature

Experimental study on tin slag polymer concrete strengthening under compression with metallic material confinement

Studies on the external strengthening of tin slag polymer concrete by fibre-reinforced plastic confinement have provided strength enhancement of tin slag polymer concrete up to 128% with carbon fibre-reinforced plastic confinement. However, the effect of metallic material confinement has yet to be studied. This article presents the experimental finding on tin slag polymer concrete strengthening through metallic material confinement under compressive loads. Machined mild steel metal tube has been employed to strengthen tin slag polymer concrete core in partial and fully confinement prior to compression testing. Through this study, compressive strength of tin slag polymer concrete short column has been enhanced with the metal tube confinement application from 59.19 MPa (unconfined) to 95.86 MPa (partial metal confinement) and 131.84 (full metal confinement) representing 61.95% and 122.74% of strength enhancement percentage. Material behaviour analysis through stress versus strain curves has revealed that the strain softening curve is modified by metal tube confinement before a fracture occurs on both partial and full metal confinement samples compared to the control sample (unconfined). In addition, the failure modes have indicated that the high ductility of metallic confinement material has effectively confined tin slag polymer concrete from sudden fracture where the metal tube in partial confinement indicates ductile expansion while the metal tube in full confinement has shown ductile crushing. In general, it was concluded that metallic material confinement on tin slag polymer concrete under compressive load has resulted in providing strength enhancement and modified the failure mode of tin slag polymer concrete. Finally, further research is recommended, especially by initiating numerical analysis to facilitate parametric studies on tin slag polymer concrete for structural material design

Combination of frustra shapes with cross sections and trigger circles for crash box design to absorb energy

Crash box that has not been maximal in absorbing energy during collisions are the basis for researchers to redesign crash box. There are three designs of crash box that combined frustra, cross section with three holes. This is a novel design that is expected to absorb more energy and minimize deformation and also buckling. The finite element simulation shows that the square model can absorb higher energy than the other two models, that is 142.66 KJ at 0.005 s, a force of 5728 KN, and displacement of 57 mm. Therefore, the recommended shape from this research is the square model