Degassing Process Influence on Tensile Strength of Neat E132 Epoxy Polymeric Materials

During the composite’s fabrication process, one of the most common defect occurs is void. Numerous literatures have suggested that the presence of void negatively affect its mechanical properties and effective degassing process is one the solutions for such issue. In this study, experiments were carried out using neat E132 epoxy to investigate the effects of different degassing process (hot water, ultrasonic bath, and vacuum) on its tensile strength. The duration of its process was carried out from 5 – 9 minutes for hot water and ultrasonic bath where vacuum process was extended until 10 minutes to observed limiting behavior. It is found that the vacuum degassing method is the most effective. Vacuum degassing process displayed the least formation of bubble and micro voids even for 10 minutes. It is also revealed that vacuum degassing process resulted the highest average tensile strength at 48.8MPa. Such findings would facilitate the well bonded effective nanocomposite fabrication process.

ON INVESTIGATION OF TENSILE STRENGTH OF COMMERCIAL SYNTHETIC NON-ABSORBABLE SUTURE MADE FROM OF BLUE POLYPROPYLENE MONOFILAMENT

Objective: The purpose of this research is to investigate the tensile strength of commercial synthetic non-absorbable suture made from blue polypropylene monofilament that commonly used in surgery.Methods: The commercial synthetic non-absorbable made from blue polypropylene monofilament was prepared for this purpose. The ASTM C1557-03 was used as a standard the method for analysis. For accuracy of the measurement, the diameter of the sutures was measured using optical microscope. The tensile strength, strain at failure, and modulus elasticity of the sutures were measured following instruction from the standard test method. The graph strain versus stress was provided.Results: Results show that that the average tensile strength of five valid tested samples is about 875.812 MPa. The average strain is found about 0.282. The average of modulus of elasticity is 4026.069 MPa.Conclusion: It is concluded that the sutures of commercial synthetic non-absorbable suture made from blue polypropylene monofilament having linier elastic as well as plastic properties. The average tensile strength of five valid tested samples is about 875.812 MPa. The average strain at failure is found about 0.282. The average of modulus of elasticity is 4026.069 MPa.

Development of a Composite Material Based on Polymers Polydimethylsiloxane and Polytetrafluoroethylene Use in Human Prosthetic Coatings

The purpose of this study is the development of a composite material composed of a main layer of polydimethylsiloxane (PDMS) and a reinforcement of polytetrafluoroethylene (PTFE), to be used later in human prosthesis coatings. A mass ratio of the main layer consisting of PDMS:Tetraethyl orthosilicate (TEOS):Di-n-butyl tin dilaurate (DBTL) in the range of 33:1:0.5; 25:1:0.5; 10:1:0.5, and the mass ratio of the composite material (PTFE:PDMS) with a range was evaluated of 1:9; 1:1; 2:3. Obtaining the following results: Tensile strength of 0.085 MPa based on the ratio of 33:1:0.5 - 1:9 and 0.59 MPa with respect to the ratio of 10:1:0.5 - 2:3, evidencing an increase in tensile strength by decreasing the weight of PDMS and increasing the weight of PTFE. On the other hand, the composite material obtained is hydrophobic, insoluble in ethanol and water, has a cross-linking percentage of 98.74 % and 99.66 % respectively, also has a minimum permeance of 5.24x10-7 (g Pa-1 s-1 m-2). With which it is concluded that the treatment whose properties resemble the human skin is the combination 10:1:0.5 - 1:1 that allowed to obtain an average tensile strength of 0.66 MPa, average modulus of elasticity of 6.56 MPa, similar to the dermis of a 43 year old person.

Performance of Embeded of Precast Beam Type Wet and Dry Joint at Maximum Moment

Research of perform of embedded precast beam was result many data (a) average tensile strength of joint between plate embedeed with plate joint was 628,55 Mpa (b)average tensile strength of joint between plate with reinforce bar D12,59 was 597,16 Mpa for tensile strength of plate with failure at reinforce bar (c) average tensile strength of reinforce bar D12,59 was 605,23 Mpa and yield strength was 425,87 Mpa (d)average tensile strength of plate 4,58 mm thick was 456,86 Mpa and yield strength was 335,02 Mpa. For welded joint need several control quality so that no hole in that perform of welded couse can decrease tensile strength of joint. Conclusion of this research is embedded for precast concrete type wet and dry can be used for construction of joints of beam.

Research on Three-Roll Screw Rolling Process for Ti6Al4V Titanium Alloy Bar

The effects of both the microstructure and the original grain size on three-roll screw rolling process of Ti6Al4V titanium alloy bar were studied in the present work. The microstructure of Ti6Al4V titanium bar had a great influence on the mechanical properties of the rolling bar. When the original size was large, the grains were apparently refined but the microstructure was uneven. But for semi-finished titanium bar composed of fine equiaxed grains, the grains after rolling were fine and uniform. During the rolling process, the Ti6Al4V titanium alloy microstructure changed from equiaxed structure to the basket-weave one. After annealing at 800℃ for 1.5 hours and then cooling in air, the average tensile strength decreased from 984 MPa to 964 MPa; while after annealing at 950℃ for 1.5 hours and then cooling by water, and aging at 540℃ for 6 hours then cooling by air, the average tensile strength increased from 979 MPa to 1107 MPa.

Differences Strength of Low Carbon Stainless Steel St 37 with Electrical Welding Compound V Use Materials Add Electrodeof Type-RB and Type -RD

This study aims to determine the difference in tensile strength of low carbon steel St 37 which is welded with RB type and RD type electrodes. The welding utilizes the type of a V-shaped joint with an angle of 600. After low carbon steel St 37 is then subjected to a tensile strength test / tensile test to obtain a tensile strength value. This research uses experimental method by preparing the object of research in the form of tensile test specimen which amounted to 19 pieces and separated into 3 groups. Group I was an untreated / non-welded St 37 carbon steel, a Group II of low carbon steel St 37 welded with RB type electrodes, and a Group III of low carbon steel St 37 welded with RD type electrodes. The cooling medium used after welding is air. The tensile test results show that the average tensile strength of low carbon steel St 37 without welding has a tensile strength of 48.02 kg/mm2 with the largest specimen tensile strength of 48.33 kg/mm2 and strength At the low carbon steel welding St 37 using RB type electrode has an average tensile strength of 29.86 kg/mm2 with the tensile strength of the largest specimen of 34.51 kg/mm2 and the tensile strength of the lowest specimen is 25.00 kg/mm2. While on the low carbon steel welding St 37 using RD type electrode has an average power of 31.83 kg/mm2 with the tensile strength of the largest specimen is 34.51 kg/mm2 and the tensile strength of the lowest specimen is 25.81 kg/mm2. Based on the analysis and T test of low carbon steel welding ST 37 using RB type electrode and RD type there is no significant tensile strength difference

Macro-Observation of the Interface of the Al-22%Si-Cu/Al-7%Si-MG Bi-Metal Parts Fabricated by Thixoforging

Thixo-forging has been proved to be able to fabricate bi-metal parts with a complex outline and a relatively regular interface economically. These products have potential applications on high volume stability radiators, brakes, and pistons. However, it is very difficult to evaluate the curved interfaces by micro observations. In this work, Al-22%Si-Cu/Al-7%Si-Mg bi-metal parts were fabricated by thixo-forging; state of the interfaces of the bi-metal parts was investigated by X-ray flaw detector observations and tensile test; optical microscope (OM) observation and scan electron microscope (SEM) observation were applied to assist the analysis. The results show that the metallurgical bonding of the interfaces is of good quality. No large scale flaw was found on the interface in X-ray flaw detector observation. It was found that higher forging pressure decreased the size of the crack on the interface and in the matrix. However, higher forging pressure can slightly improve tensile strength. Large ratio of fresh interface relates to original interface resulted in a slightly better tensile strength. Without heat-treatment, the bi-metal forgings have an average tensile strength of 106 MPa. T6 heat treatment blunted the blades of the plate like crack and nodulized the defects, T6 heat treatment also decreased the size of the Si particles. As a result, the average tensile strength of the bi-metal forgings increased to 200 MPa.

Mechanical Properties of Single and Double-Layered PVA Nanofibers

Multi-layered nanofiber textiles can be utilized in many applications. In such case the individual layers are laid in more stages and the question arises whether the connection is perfect. Two kinds of samples of PVA nanotextiles having the weight of 1.3 g/m2 (single-layered, AI) and 2.8 g/m2 (double-layered, AII), respectively. It was shown that mechanical properties, in particular the average tensile strength (24 N/mm for AI and 51 N/mm for AII) and stiffness (950 N/mm for AI and 1600 N/mm for AII), are independent of the number of layers, only their weight per unit area matters. This indicates that the bond between the individual layers is perfect.

Effects of High Temperature on Tensile and Bending Strengths of T300 Carbon Fiber Three Dimensional Braided Composites

In this paper, the tensile and bending strengths of T-300 carbon fiber three dimensional braided/epoxy resin composites at 23 oC and 150 oC were researched. The results indicate that the effect of temperature on the tensile strength and bending strength of three dimensional braided composites is sentitive. However high temperature makes bending strength of 3D braided composites lost more than that of tensile strength of 3D braided composites. The average tensile strength of 3D braided composites at 150 oC is 65.06% of average tensile strength of 3D braided composites at 23 oC. The average bending strength of 3D braided composites at 150 oC is only 11.44% of average bending strength of 3D braided composites at 23 oC. This means that application temperature should be taken into account when 3D braided composites are used.

Study of the Preparation and Degradable Characteristics of CaCO3-PE Film

The CaCO3-polyethylene (PE) film was prepared by filling method, and the filling amount of calcium carbonate in film was 20%(w/w). The effects of natural weathering, ultraviolet light irradiation on the tensile strength, breaking elongation and molecular weight of the CaCO3-PE film was investigated comparing with the photosensitizer-PE film. After being located in the open air for 30 d, the average tensile strength, average breaking elongation and the mean molecular weight of CaCO3-PE film decreased 80.6%, 99.3% and 25.3%, respectively, as for the photosensitizer-PE film, the corresponding items decreased 18.8%, 45.0% and 11.7%, respectively. After ultraviolet light irradiation for 120 h, the average tensile strength of CaCO3-PE film decreased 29.9%, the average tensile strength of the photosensitizer-PE film, however, increased 20.5%. The average breaking elongation of CaCO3-PE film and photosensitizer-PE film decreased 97.3% and 84.1% respectively, the mean molecular weight of both films decreased 66.7% and 26.6% respectively. After covered by soil for 200 d, the weight loss of the CaCO3-PE film and photosensitizer-PE was 2.15% and 0.22%, respectively. The results showed that the degradability of CaCO3-PE film is superior to the photosensitizer-PE film.