No abstract

A research has been conducted in the present study to investigate the effect of hole configuration on tensile strength of lontar fiber-reinforced composites. The lontar fiber-reinforced composites used in this study were produced by hand lay-up process. The lontar fiber-reinforced composites consist of short random fiber of 5 cm that contains 32% of nominal fiber volume as the reinforcement and unsaturated polyester as the matrix. The results show that the differences of hole configuration have an effect on tensile strength of lontar fiber-reinforced composites. It is found that the specific area of four-hole specimens experiences smaller strain propagation due to the redistributed stress and no stress passes through the hole. The damage of lontar fiber-reinforced composites with different hole configurations in tension is fairly straight and transverse to the loading axis, where the initial damage occurs in the form of matrix cracking, propagates into interfacial failure in form of delamination, and ultimately failed mainly due to the fiber breakage.

The aim of this study is to understand the thermal phenomenon of unidirectional Glass Fibre Reinforced Polymer (GFRP) composite under static and fatigue (tensile) loads. This study used a rectangular shaped GFRP composite and consisted of specimens with and without a circular notch. Under static test, the constant displacement rate was applied. Under fatigue test, frequency and amplitude of stress were explored to study the fatigue properties and damage evolution of the specimen. Thermography was used in real-time observation to obtain the temperature profile on the external surface of the specimens. This experimental method showed that the thermal phenomenon gave a good detection of the damage appearance of GFRP material under static loading. Moreover, thermal phenomenon gave a good correlation with the energy dissipation under fatigue loading. Thermal phenomenon successfully determined the high cycle fatigue strength of GFRP composite. This study concluded that thermal phenomenon observed by Infra-Red (IR) camera has successfully demonstrated the damage propagation and the strength behaviour of GFRP composite due to tensile loading in both static and fatigue conditions. The IR camera can then be used to determine the damage evolution and the strength prediction based on the thermal phenomenon on the external surface of the GFRP composite.

This work presents an experimental study to monitor the damage propagation of composite material by non destructive testing (NDT) method. In order to achieve this, an open hole condition of glass fiber/epoxy composite has been used as the specimen test under static tensile loading and observed using two different real-time monitoring techniques of NDT namely infra-red (IR) camera and supported by Acoustic Emission. The results show that the thermal response and acoustic emission signals give a good detection on damage appearance and damage propagation of glass fiber/epoxy composite under static tensile loading conditions.

Industri garam di Provinsi Nusa Tenggara Timur masih menggunakan cara manual dalam proses pencampuran garam dengan yodium yaitu dengan cara mengaduk bolak-balik setumpuk garam yang telah disemprotkan larutan iodat dalam garam dengan konsentrasi tertentu. Pencampuran seperti ini sangat tidak praktis, efisien dan efektif. Dari permasalahan tersebut perlu dilakukanya Rancang Bangun Mesin Mixer Iodisasi Garam Halus Sistem Injeksi  Skala Home Industri Dengan Metode VDI 2222 yang bertujuan untuk membantu proses iodisasi garam di Provinsi Nusa Tenggara Timur sehingga produksi garam konsumsi sesuai standar SNI 3556. Dari hasil perancangan menghasilkan mesin mixer iodisasi garam dengan wadah berbahan stainless steel berkapasitas 25 kg, pengaduk tipe dayung dengan putaran 60,76 rpm yang digerakan oleh motor listrik 0,5 HP 1400 rpm dengan menggunakan transmisi kombinasi puli dan sabuk untuk memperkecil putaran.  Sistem penyemprotan menggunakan sistem injeksi dengan tekanan berasal dari pompa DC 12 V dengan kecepatan aliran nozzle , kecepatan aliran  dan daya pompa 36 watt. Hasil pengujian kandungan yodium pada garam krosok sebelum proses iodisasi adalah 0 ppm, kemudian dilakukanya proses iodisasi dengan perbandingan komposisi pencapuran 25kg garam krosok, 1,25g kio3 dan 25ml air dan lama waktu pengadukan pada pengujian 1 = 3 menit,  pengujian 2 = 4 menit dan pengujian 3 = 5menit. Dan setelah dilakukanya proses pengadukan sehingga menghasilkan garam dengan kandungan yodium pada pengujian 1= 55,65 ppm, pengujian 2 = 53,83 ppm dan pada pengujian 3 = 49.16ppm. Dengan adanya alat ini nantinya diharapkan dapat meningkatkan kualitas prokduksi garam di NTT.