Papers by Keyword: Compliance

Abstract: This study examines the performance of hybrid steel-GFRP pipes compared to steel pipes, with a focus on bonding properties and the occurrence of internal corrosion. Some pipes were worn screw-shaped to mimic the effects of corrosion. The hybrid material was manufactured from two steel pipes reinforced with GFRP, bonded with polyester resin and 10% styrene to reduce viscosity and prevent bubble formation. Distortion problems during the manufacture of the specimens are addressed. Results indicate greater deformation in the worn pipes than in the steel-only specimens, whereas the hybrid material showed no significant difference between the two types. The hybrid material supported higher loads in some probes, but only two hybrid probes failed. Strain gauges measured the deformations, and the composite material's behavior was examined under a microscope. The hybrid material presented a lower flexural modulus and greater compliance to cracking. Despite the performance of the proposed hybrid material not being able to stand up to steel’s superior mechanical properties, the study offers useful insights and recommendations for future research, backed by stress-strain graphs.

Abstract: The main motivation in stamping die industry and academia is panel quality and formability issues rather than the weight and cost of the die. A product should be designed according to the loads that it can be faced in service condition. But somehow this rule is not valid for stamping die design since the minimum distance between the ribs is based on the standards and location and pattern of the ribs which are depending primarily on the company experience. In this work, an auto panel drawing die design is investigated numerically whether it is overdesigned or not. The loads on the die surfaces are calculated by numerical methods. When a panel is drawn between upper and lower die, the contact pressure (CP) occurs on the interface surfaces due to this interaction. Since CP is a vital parameter and it is almost impossible to measure it by experimental methods, it is validated by two different numerical codes. The CP values obtained from Autoform^® quasi-static solution are compared with Abaqus^® transient forming analysis solution. Topology optimization is applied on the lower die by using the estimated CP loads. Von-Mises stress, elastic deformation and volume are compared between current and optimized die geometry. Panel thickness variation is also investigated in longitudinal and transverse directions.

Abstract: Under the influence of the processes of intensification of relations among internal and external environment of companies the necessity of compliance to international standards is rising significantly. There is a growing need for a deep understanding of corporate relations, using of control mechanisms over the company, demands for its transparency, balance of stakeholders interests and rights. These processes determine the effectiveness of corporate security systems. Currently, the capacity to implement effective management of corporate security involves the development of a business approach that creates long-term shareholder value by combining use of opportunities and risk management that meet applying to international standards and practices. The concept of security is mainly designed for a long period of time. With the development of open market relations and strengthening of legal regulation of the market measures, the emphasis of security has been transferring to the sphere of economy. Security becomes an essential priority for any kind of business interaction. In order to find out where security problems currently stand in practice and within academia circles the relevant sources of information were analyzed. The result of formalization, generalization of best international management practices and expertise are defined in international standards. In the article the content of the application and features of standards relating to key aspects of corporate security at the national and international markets are considered.

Abstract: Tubular drive shafts are subjected to combined axial tension, torsional moment and bending moment. The structural integrity of the driveshaft is investigated by evaluating the change in strength, stiffness and the life of the driveshaft with the change in the crack length. A review of driveshaft failure analysis case histories identifies circumferential crack and arbitrarily oriented cracks to be critical. The singular stress field around a crack tip in a general shell structure is characterized by mixed mode membrane and bending stress intensity factors. Accurate determination of these stress intensity factors (less than 1%) are carried out by a subprogram named as 3MBSIF. The validation of Finite element model using ABAQUS and post processing subprogram 3MBSIF together is carried out using benchmarks, a set of standard test problems with known target solutions. Further SIFs are derived for cylindrical shell and the driveshaft under the action of bending moment. To quantify the change in the compliance of cylindrical shell and the driveshaft with change in crack lengths is studied by performing Modal Analysis. It was observed that the variation in frequency is higher for smaller crack angles.

Abstract: A methodology and a procedure for topology optimization of wing structure based on manufacturing constraints were proposed. By the methodology and procedure proposed, topology of thin-box wing structure which is easier manufactured than traditional topology result can be obtained. The manufacturing constraints of draw direction, member size control and inexcusable initial design were introduced into the optimal procedure and executed in Optistruct. Effect and efficiency were analyzed and compared with traditional topology optimization.

Abstract: Low molecular weight materials from low density polyethylene (LDPE) were detected and the results were compared with the legal regulations imposed by China and the United States of America. Four types of films were tested using ASTM D 5227 imposed by USA while two resin samples underwent a test according to the standard method GB/T 5009.58-2003 of China Regulation. Applicable legal compliance used was the U.S. Food and Drug Administration (USFDA) and China Food Hygiene Law. All LDPE grades from local manufacturers comply with US FDA CFR 177.152 Specification 2.1, 2.2 and 2.3 except for D2 grade which failed to meet the specification 2.2. For China Food Hygiene Law, C1, D1 and D2 samples failed to meet the specified standard. This study also highlighted the result obtain testing the resin and film for both compliance tests.

Abstract: Compliance is one of the main requirements to be satisfied by a gripper system. The paper addresses this issue and proposes a compliant, pneumatic muscle actuated gripper system. Constructive and functional models of an innovative gripper system are presented, together with a discussion of its limits.

Abstract: The paper is focusing on the investigation of the effective crack length obtained from bending test on concrete notched beams with the complementary measurements of ultrasound passing time through the tested concrete specimen. The ultrasound passing time measurements are performed on several stages of the fracture process along the specimen ligament for each tested notched beam. Gained results of the time of ultrasound pulse needed to pass through specimens' failure zone, i.e. its dependence on the crack length or opening, provide information which may help to identify the process of crack formation without the visible indications. The fracture tests are conducted for a set of specimens differing in the notch length. Changes of the ultrasound passing times with increasing effective crack length are observed and discussed.

Abstract: A crankshaft is the most critical component, and it can dominate the life of the engine. Nowadays an orbital grinding is widely used to grind a crankshaft. In this study, static analysis is done to find deformation of an orbital grinding system due to weight, modal analysis is done to obtain the natural frequencies, and harmonic analysis is done to investigate the compliance. It is found that all the results show that first frequencies are found to be near 70-80Hz. The machine will be weak to vibration near 70-80Hz. It is also found that the peak value of x compliance is smaller than that for other axes, and grinding in the x direction will be more stable than grinding in other direction.

Abstract: A pulsatile circulation system has been built to simulate aortic blood flow. The system has both upstream and downstream compliances and resistances to simulate the elasticity and resistances of blood circulation system. Influences of the compliances and resistances on the pulsatile pressure waveforms have been systematically studied using this system. We found that in absence of the compliances and the downstream resistance, it results in an oversize negative pulsation to the pressure waveforms. The downstream resistance hardly affects the structure of the pressure waveforms, whereas the mean amplitude of pressure increases along with the downstream resistance. The compliance can reduce the peak value of the pressure, which is unrelated to the location of the compliance but related to the elasticity in the system. With fixed upstream system elasticity, the pressure waveform is more stable.