Comparison the Strength of Midship Structures With Margin Plate and Without Margin Plate

Margin plate is a part of bottom construction that joint the floor and frame construction of the ship, so the inner bottom plate will be installed cut off on the margin plate. Lately the bottom construction of the ship tends not to use the margin plate. The ship is currently built with an inner bottom plate continuously from the left side to the right side of the ship.This study aims to determine the transversal and longitudinal strength ratio of ships with and without margin plate. The analysis was carried out by using Finite Element Method so-called ANSYSTM. The result shows if the loadvariatied 0.2 x maximum load on the calculation of the transverse strength of the ship, the stress value on the ship model with a margin plate was 9.6242 (N/mm2) and on the ship model without margin plate was 8.4739 (N/mm2) under conditions 100%. The results of the comparison due to bottom load averaged 15.82%. The difference in stress due to the effect of deck loads was an average of 13.49% while the effect of side loads was on average 8.74%. The longitudinal strength of the ship was also a varied of every increase of 0.2 x maximum moment with a review point of meeting between bottom plate and bilga plate for the ship model without margin plates using the Multi Point Constraint (MPC) method looking for results in sagging conditions of 12,443 (N / mm2) and the hogging condition was -11.045 (N / mm2) at 100% x maximum moment load conditions. So that the ship model with a margin plate sagging condition was 23,189 (N / mm2) and hagging condition was -20,585 (N / mm2). The results showed the stress that occurred in the ship model without using margin plate was better to withstand the transverse and longitudinal strength of the ship compared to the ship model with the margin plate.

Ankle joint rotation and exerted moment during plantarflexion dependents on measuring- and fixation method

We examined the effect of ankle joint fixation vs increased foot pressure (aiming to reduce dynamometer-subject elasticity (DSE)) on the exerted moment during plantarflexion contraction. We also examined the joint rotation in dependence of the measuring site (forefoot, rearfoot) and the foot condition (fixed, free). We hypothesized higher exerted moments due to reduced DSE compared to fixed condition and an effect of fixation on the joint rotation in dependence of the measuring site. Fourteen healthy individuals (28.7±6.9y) completed in randomized order maximal isometric plantarflexions in four different positions (0-3-6-9 cm) and two ankle joint conditions (fixed-free). Kinematics of the rear- and forefoot were obtained synchronously. We found higher moment in the fixed compared to the free condition at all positions. The maximum moment in the fixed condition did not differ at any position. At the fixed condition, the forefoot rotation did not differ at any position (~5°) while at free condition we observed a significant rotation reduction (form ~12 to ~5°). The rearfoot rotation did not differ between conditions at any position while a significant joint angle reduction was observed (~10 to ~6° and ~12 to ~6°; fixed-free respectively). The results indicate that with appropriate foot fixation the maximum moment can be achieved irrespective of the position. With the foot secured, the measuring site influences the rotational outcome. We suggest that for a minimization of the joint rotation a fixation and the forefoot-measuring site should be preferred. Additionally, for unconstrained foot kinematic observations both measuring sites can be obtained.

Analisis Tahapan Konstruksi Jembatan Cable Stayed dengan Metode Kesetimbangan Kantilever

ABSTRAKJembatan cable stayed merupakan struktur jembatan yang memiliki sederetan kabel yang menghubungkan pilon dan girder. Dalam pembangunan jembatan cable stayed perlu dilakukan analisis pada tahap konstruksi. Penelitian ini menganalisis tahapan konstruksi jembatan cable stayed menggunakan metode kesetimbangan kantilever untuk menghasilkan besarnya gaya-gaya dalam yang memenuhi syarat. Berdasarkan hasil penelitian, tegangan kabel maksimum yaitu 404,6 MPa dengan tegangan putus yaitu 837 MPa. Nilai lendutan terendah terdapat pada segmen 1 yaitu 0,001 m. Nilai lendutan tertinggi terdapat pada segmen 20 yaitu 0,167 m. Kemudian mengalami penurunan pada tahap 21 sebesar 0,153 m. Lendutan yang terjadi memiliki nilai di bawah lendutan izin yaitu 0,375 m. Momen terbesar terjadi pada segmen 21 yaitu 18.286,31 kNm; sedangkan yang terendah pada segmen 11 yaitu 20,43 kNm. Momen maksimum yang terjadi akibat layan yaitu 68.003 kNm dengan batas kapasitas izin yaitu 190.500,13 kNm. Berdasarkan hasil yang diperoleh, dapat disimpulkan bahwa struktur jembatan aman pada tahap pelaksanaan dan juga pasca konstruksi.Kata Kunci: cable stayed, tegangan kabel, lendutan, gaya dalam ABSTRACTThe cable-stayed bridge is structure of a bridge that have an align of cables which connecting to a pilon and a girder. Through a cable-stayed bridge constructor, it is necessary to construge stage. This research analyzing a phase of constructor a cable-stayed bridge using equilibrium cantiveler method's to produce a within forces which is fullfill requirement. According to the result of the research, the highest tension of the cable is 404.6 MPa and ultimate tension is 837 MPa. The lowest deflection value occur at the segment 1 is 0.001 m. The highest deflection value occur at the segment 20 is 0.0167 m. Subsequently undergo decreasing on the phase 21 is 0.153 m. The deflection that occur has value below the deflection permit is 0.375 m. The highest moment occur at the segment 21 is 18,286.31 kNm; on the other hand the lowest moment occur at the segment 11 is 20.43 kNm. The maximum moment that occurs due to the service is 68,003 kNm with a permit capacity limit og 190,500.13 kNm. According to the result of the research, so that in conclude, the structure is safe on the execution phase and also the post-construction phase.Keywords: cable stayed, tension cable, displacement, beam force

Wrench Capabilities of a Kinematically Redundant Planar Parallel Manipulator

SUMMARY This paper presents a methodology to obtain the wrench capabilities of a kinematically redundant planar parallel manipulator using a wrench polytope approach. A methodology proposed by others for non-redundant and actuation-redundant manipulators is adapted to a kinematically redundant manipulator. Four wrench capabilities are examined: a pure force analysis, the maximum force for a prescribed moment, the maximum reachable force, and the maximum moment with a prescribed force. The proposed methodology, which finds the exact explicit solution for three of the four wrench capabilities, does not use optimization and is very efficient.

Comparison of two starting options for conveyor belt electric drive

The purpose of the paper is to study the energy and operational parameters of a belt conveyor under two starting methods: direct and frequency. Taking into account the non-linearity of the mathematical description of belt conveyor mechanical part and induction motor drive, the analysis of starting modes is carried out by the method of nonlinear differential calculus where equivalent masses are replaced with the discrete ones. The calculations are performed on the models using MATLAB. It is found out that the use of a frequency converter for the conveyor allows to reduce the maximum current by 4.7 times when starting the motor; by 2.5 times the maximum moment; by 1.52 times the maximum moment of resistance forces on the motor shaft; by 8.68 times the maximum value of power losses in stator windings; by 10.2 times the total power losses; by 2.9 times the power consumed from the network; by 3.4 times the amount of energy losses in the stator windings; by 3 times the total energy losses; by 1.25 times the energy consumed from the network; by 3 times the maximum acceleration of the belt; by 3 times the overshooting values during transients by the values of leading tension forces of the belt on various sections of the conveyor; by 1.875 times the transients duration in terms of the leading tension forces of the belt on different sections of the conveyor. The developed mathematical model of the belt conveyor makes it possible to obtain quantitative estimates of energy and operational parameters of the installation under two starting methods: direct and frequency. The use of frequency start-up of the conveyor allows to decrease motor energy losses by 3 times. It also reduces motor heating as well as decreases the maximum values of belt tension forces on various sections of the conveyor by more than three times.

Numerical Solution of Euler's Rotation Equations for a Rigid Body about a Fixed Point

Finding a solution for Euler's equations is a classic mechanics problem. This study revisits the problem with numerical approaches. For ease of teaching and research, a Maple code comprising 2 lines is written to find a numerical solution for the problem. The study's results are validated by comparing these with previous studies. Our results confirm the correctness of the principle of maximum moment of inertia of the rotating body, which is verified by thermodynamics. As an essential part of this study, the Maple code is provided.

Investigation of Circumferential Internal Surface-Cracked Pipes and Elbows Tested at Conditions Similar to PWR and an “Apparent Net-Section-Collapse” Prediction Methodology

The Original Net-Section-Collapse (NSC) analysis was developed in the 1970s for prediction of the maximum (failure) moment for a circumferential flaw in a pipe, and is used widely in pipe flaw assessments. A large number of past pipe tests show that deep surface cracks can break through the thickness and result in leaks; hence, the maximum moment of that surface-cracked pipe was below the maximum moment for the circumferential through-wall crack with the same length. In these cases, the applied moment has to be increased for the resulting leak to grow as a through-wall crack. Hence, load-controlled leak-before-break (LBB) fracture behavior has been experimentally observed although it is not predictable by the Original NSC analysis. Recently, Original NSC analysis for circumferential surface-cracked pipes under combined bending and axial tension were enhanced through the development of the “Apparent Net-Section Collapse” methodology to explain inconsistencies with the Original NSC. “Apparent NSC” methodology was developed considering surface-cracked pipe test data developed from external (OD) surface-cracked pipe tests conducted at room temperature (RT) with a vast majority conducted under pure bending and unpressurized conditions. Since it is undesirable to have leakage in many applications, the deficiency in the Original NSC analysis was shown experimentally, and the recently developed “Apparent NSC” methodology applied to a carefully planned matrix of pipe and elbow tests conducted on TP304 stainless steel and Alloy600 materials with different flaw dimensions (composed of short and shallow to long and deep surface cracks), in the range of normalized crack depth, a/t = 0.4 to 0.8 and crack length, 2θψ = 90° to 180°. The tests were conducted under conditions similar to a pressurized water reactor (PWR), and consistent with the International Piping Integrity Research Group (IPIRG-2) [1] test conditions, namely a temperature of 550°F (288°C) and an internal pressure of 2,250 psi. The loads corresponding to the surface-crack initiation, maximum load, and leakage events were recorded from each of the surface-cracked pipe and elbow tests. The data were used to understand the predictable nature of the “Apparent NSC” methodology and to develop an understanding of the fracture behavior of surface-cracked pipes leading to correlation of these results to LBB behavior. Further, the results were correlated between the material composition and the variation of the experimental and predicted bending stress from NSC loads to observations from the previous IPIRG-2 program, where the experimental burst loads were characterized with respect to the flow stress assumptions. The material composition such as variation in sulfur content, and the crack-initiation and crack growth based on elastic-plastic fracture mechanics were used to explain the variability of the flow stress assumption when used in a NSC/limit-load type of analysis. The investigation also showed comparison of predictions based on various flow stress (σf) definitions assumed using yield and ultimate stresses obtained from the tensile tests conducted on the pipe and elbow materials at 550°F (288°C) and applied to the Original NSC and “Apparent NSC” methodologies. The moment predictions using ASME elbow stress indices (B2, C2 used in design) or the IPIRG-2 parameter (Ψec) for the circumferentially surface-cracked elbows were also compared to the experimental maximum moments for the tested elbows.

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.

Biomechanical Evaluation of an Augmented Medial Capsular Repair for Hallux Valgus Surgery

Category: Bunion Introduction/Purpose: Hallux valgus correction is often complicated by recurrence in the setting of inadequate soft tissue balancing. The etiology of recurrence is multifactorial, but a key factor is the quality of the medial capsulorrhaphy which is limited by the quality and strength of the soft tissues. These soft tissues are often attenuated with loss of integrity due to the longstanding bunion deformity. We hypothesize that the medial capsulorrhaphy augmented with a suture tape construct will create a stronger repair. Methods: 8 unmatched and 16 matched cadaveric foot specimens were prepared. None had bunion deformities. The 8 unmatched samples were tested to determine the strength of the native medial capsule. The 16 matched samples underwent a longitudinal medial capsulotomy, eminence resection and medial capsulorrhaphy with or without augmentation with a suture tape construct. The samples were then tested in a biomechanics lab to determine the strength of the medial capsulorrhaphy. Results: The mean maximum moment for the intact, capsular repair and suture tape groups were 2.19 ± 0.639 Nm, 0.225 ± 0.074 Nm and 0.968 ± 0.581, respectively, P<0.001. The mean stiffness for the intact, capsular repair and suture tape groups were 8.06 ± 3.75 N/mm, 1.463 ± 0.553 N/mm, and 4.438 ± 4.035 N/mm, respectively, P=0.003. The suture tape provided 4.3x higher maximum moment and 3x higher stiffness compared to traditional medial capsulorrhaphy. Conclusion: The study demonstrates that a medial capsular repair augmented in a cadaveric model of medial capsulorrhaphy to provide greater strength compared to conventional suture repair. Recurrence of hallux valgus after surgery is multifactorial. One element is the strength of the medial imbrication and capsular repair at the 1st metatarsal phalangeal joint (MTPJ). The study presents biomechanical data demonstrating that this repair is strengthened with suture tape augmentation at the medial 1st MTPJ. This may result in decreased recurrence and potentially improved patient satisfaction following bunion correction.

Pembesaran Gaya Dalam pada Elemen Struktur untuk Berbagai Zona Gempa di Indonesia. (Hal. 26-38)

ABSTRAKKombinasi beban pada struktur bangunan harus diperhitungkan dalam mendesain penampang elemen struktur. Hasil kombinasi beban gempa mempengaruhi peningkatan pembesaran gaya-dalamnya terhadap hasil kombinasi beban tanpa gempa. Penelitian ini bertujuan untuk memprediksi pembesaran gaya-dalam akibat beban gempapada menara pandang 6 lantai bermaterial beton dengan 8 model variasi beban, yaitu: beban tanpa gempa, dan beban dengan percepatan 0,2g; 0,4g; 0,6g; 1,0g; 1,2g; 1,5g dan 2g. Analisis struktur dengan software ETABS v.9.7.2 menghasilkan pembesaran lentur sebesar 11,4 untuk tumpuan dan 2,49 kali untuk lapangan; geser sebesar 3,99 kali pada tumpuan dan 40,72 kali pada lapangan; dan normal tidak signifikan perubahannya pada balok. pembesaran gaya-dalam pada kolom tumpuan yaitu sebesar 1,27 kali normal, 663,2 kali geser; 55,84 kali lentur M2 dan 487,2 kali lentur M3. Hasil nilai pembesaran ini dapat digunakan sebagai referensi nilai pembesaran momen maksimum terhadap kombinasi beban tanpa gempa dalam desain awal.Kata Kunci: struktur gedung, beban gempa, pembesaran, momen, geser, normal. ABSTRACTThe combination of loads on building structures must be calculated in designing the cross-section of structural elements. The results of combination of earthquake loads influenced an increasing magnitude of the force againts the results of a combination of without earthquake loads. This study intends to predict the magnification of the internal force due to the without earthquake loads on a 6-story tower with concrete material, with 8 variation models of load such as: load without earthquake, and load with acceleration of 0,2g; 0,4g; 0,6g; 1,0g;, 1,2g; 1,5g; and 2g. Structural analysis using ETABS v9.7.2 software results that the magnification of the flexural is 11,4 and 2,49 times for the center of the beam, and insgnificant changes for normal in the beam. The magnification of internal force in the pedestal column is 1,27 time for normal, 663.2 time for shear, 55.84 times for M2 and 497.2 times for M3. The results of this magnification value can be used as a reference to the value of the maximum moment magnification of a combination without earthquake in the initial design.Keywords: building structure, earthquake load, magnication, moment, shear, norma.