Nonlinear deflection analysis of helical spring in elastic-perfect plastic material: Application to the plastic extension of piano wire spring

2021 ◽  
pp. 103971
Author(s):  
Hiroyuki Kato ◽  
Hitoshi Suzuki
Keyword(s):  
Plastic Material ◽  
Helical Spring ◽  
Deflection Analysis ◽  
Plastic Extension ◽  
Piano Wire ◽  
Perfect Plastic

Comparison of Different Methods for Stress and Deflection Analysis in Embedded Die Packages during the Assembly Process

2014 ◽  
Vol 2014 (1) ◽  
pp. 000355-000360
Author(s):  
K. Macurova ◽  
R. Bermejo ◽  
M. Pletz ◽  
R. Schöngrundner ◽  
T. Antretter ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Plastic Material ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Element Model ◽  
Analytical Investigation ◽  
Circuit Board ◽  
Curvature Radius ◽  
Assembly Process ◽  
Deflection Analysis

Important topics for electronic packages are thermally induced stresses created during package manufacturing and their role in mechanical failure. In the present paper, an analytical and a numerical analysis of the assembly process (component attached with an adhesive to a copper foil) is investigated. This process is prior to the lamination of the printed circuit board. Stresses develop due to a mismatch of coefficients of thermal expansion and particularly to shrinkage associated with adhesive polymerization. The analytical investigation is based on the classical laminate theory and an interfacial model. The three-dimensional numerical finite element model is capable to use geometric and material properties which are not possible to investigate analytically. In particular, the influence of the adhesive meniscus and plastic material models for copper and adhesive are investigated. The models are validated experimentally by an X-ray diffraction method (Rocking-Curve-Technique) showing a good agreement of the calculated and measured curvature radius values.

Comparison of Different Methods for Stress and Deflection Analysis in Embedded Die Packages During the Assembly Process

2015 ◽  
Vol 12 (2) ◽  
pp. 80-85 ◽  
Author(s):  
K. Macurova ◽  
R. Bermejo ◽  
M. Pletz ◽  
R. Schöngrundner ◽  
T. Antretter ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Plastic Material ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Element Model ◽  
Analytical Investigation ◽  
Circuit Board ◽  
Curvature Radius ◽  
Assembly Process ◽  
Deflection Analysis

Important topics for electronic packages are thermally induced stresses created during package manufacturing and their role in mechanical failure. In the present paper, an analytical and a numerical analysis of the assembly process (component attached with an adhesive to a copper foil) is investigated. This process is prior to the lamination of the printed circuit board. Stresses develop due to a mismatch of coefficients of thermal expansion and particularly to shrinkage associated with adhesive polymerization. The analytical investigation is based on the classical laminate theory and an interfacial model. The three-dimensional, numerical, finite element model is capable of using geometric and material properties not possible to investigate analytically. In particular, the influence of the adhesive meniscus and plastic material models for copper and adhesive are investigated. The models are validated experimentally by an x-ray diffraction method (rocking-curve technique) showing a good agreement of the calculated and measured curvature radius values.

An Elastic-Plastic Solver of the Wheel-Rail Contact

2010 ◽  
Author(s):  
Constantin I. Ba˘rbiˆnt¸a˘ ◽  
Sulleyman Yaldiz ◽  
Alina Dragomir ◽  
Spiridon S. Cret¸u
Keyword(s):  
Plastic Deformation ◽  
Stress State ◽  
Plastic Material ◽  
Computer Code ◽  
Load Level ◽  
Analysis Model ◽  
Elastic Plastic ◽  
Circular Arcs ◽  
Plastic Analysis ◽  
Perfect Plastic

Wheel and rail in service undergo continual wear and plastic deformation at the surface, so that in time all wheel profiles will be different. The optimization by grinding a worn rail profile to minimize contact stresses requires the development of a software to reconstruct a rail profile using circular arcs. A working algorithm, able to be incorporated into a computer code, has been developed to solve the stress state in the general case of non-Hertzian contacts. To limit the pressure, an elastic-perfect plastic material has been incorporated into the computer code. The pressure distribution and the corresponding stresses states have been investigated for pure normal loadings, as well as for the combined, normal and tangential loadings. The elastic-plastic analysis model allows fast investigations regarding the influence of different parameters such as load level, contact geometry including the geometry of the worn profiles.

scholarly journals A Perfect Plastic Material for Studies on Self-Propelled Motion on the Water Surface

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3116
Author(s):  
Richard J. G. Löffler ◽  
Martin M. Hanczyc ◽  
Jerzy Gorecki
Keyword(s):  
Hybrid Material ◽  
Water Surface ◽  
Plastic Material ◽  
Petri Dish ◽  
Object Shape ◽  
Self Motion ◽  
The Relationship ◽  
Very High ◽  
Perfect Plastic ◽  
Undesirable Feature

We describe a novel plastic material composed of camphene, camphor, and polypropylene that seems perfectly suited for studies on self-propelled objects on the water surface. Self-motion is one of the attributes of life, and chemically propelled objects show numerous similarities with animated motion. One of important questions is the relationship between the object shape and its motility. In our previous paper, {R. Löffler et al. PCCP, 2019, 21, 24852–24856}, we presented a novel hybrid material, obtained from the solution of camphor in camphene, that allowed making objects of various shapes. This hybrid material has wax-like mechanical properties, but it has a very high tackiness. Here, we report that a small amount of polypropylene removed this undesirable feature. We investigated the properties of camphor–camphene–polypropylene plastic by performing the statistical analysis of a pill trajectory inside a Petri dish and compared them with those of camphor-camphene wax. The plastic showed the stable character of motion for over an hour-long experiment. The surface activity of objects made of plastic did not significantly depend on the weight ratios of the compounds. Such a significant increase in usefulness came from the polypropylene, which controlled the dissipation of camphor and camphene molecules.

Masonry: the brittle or plastic material?

2019 ◽  
pp. 22-28
Keyword(s):  
Plastic Material ◽  
Experimental Studies ◽  
Point Of View ◽  
Plastic Properties ◽  
Plastic Deformations ◽  
Base Materials ◽  
Stress States ◽  
Creep Deformations ◽  
Structural Point

The results of experimental studies of masonry on the action of dynamic and static (short-term and long-term) loads are presented. The possibility of plastic deformations in the masonry is analyzed for different types of force effects. The falsity of the proposed approach to the estimation of the coefficient of plasticity of masonry, taking into account the ratio of elastic and total deformations of the masonry is noted. The study of the works of Soviet scientists revealed that the masonry under the action of seismic loads refers to brittle materials in the complete absence of plastic properties in it in the process of instantaneous application of forces. For the cases of uniaxial and plane stress states of the masonry, data on the coefficient of plasticity obtained from the experiment are presented. On the basis of experimental studies the influence of the strength of the so-called base materials (brick, mortar) on the bearing capacity of the masonry, regardless of the nature of the application of forces and the type of its stress state, is noted. The analysis of works of prof. S. V. Polyakov makes it possible to draw a conclusion that at the long application of the load, characteristic for the masonry are not plastic deformations, but creep deformations. It is shown that the proposals of some authors on the need to reduce the level of adhesion of the mortar to the brick for the masonry erected in earthquake-prone regions in order to improve its plastic properties are erroneous both from the structural point of view and from the point of view of ensuring the seismic resistance of structures. It is noted that the proposal to assess the plasticity of the masonry of ceramic brick walls and large-format ceramic stone with a voidness of more than 20% is incorrect, and does not meet the work of the masonry of hollow material. On the basis of the analysis of a large number of research works it is concluded about the fragile work of masonry.

The Issue of Plastic and Microplastic Pollution in Soil

2019 ◽  
Vol 56 (3) ◽  
pp. 484-487 ◽  
Author(s):  
Valentina Constanta Tudor ◽  
Dorina Nicoleta Mocuta ◽  
Ruxandra Florina Teodorescu ◽  
Dragos Ion Smedescu
Keyword(s):  
Water Pollution ◽  
Organic Matter ◽  
Soil Pollution ◽  
Aquatic Environment ◽  
Negative Impact ◽  
Plastic Material ◽  
Soil Biota ◽  
Toxic Substances

Soil pollution with plastics represents a great threat to plants, animals, but especially to humans, as a very small quantity of the plastic which is discarded daily is recycled or incinerated in waste facilities, much of it reaching landfills where their decomposition lasts up to 1000 years and during this time the toxic substances penetrate the soil and the water. If, initially, the pollution with plastics has been identified and recognized in the aquatic environment, recent studies show that plastics residues exist in huge quantities in the soil. The present study focuses on the analysis of factors that pollute soil, so the various studies that have been carried out claim that soil pollution with plastic is much higher and increases in an aggressive manner, being estimated to be 4 to 23 times higher than water pollution with plastics, and the accumulation of microplastics in the soil has a negative impact on soil biota. Thus, once the plastic material accumulates in the soil, it is assimilated to organic matter and the mineral substitutes of the soil and persists for several hundred years.

EXPERIENCE OF RECONSTRUCTION OF THE BREAST WITH THE USE OF THORACODORSAL FLAP

2018 ◽  
Vol 64 (2) ◽  
pp. 206-210
Author(s):  
Petr Krivorotko ◽  
Vladimir Semiglazov ◽  
Aleksey Belyaev ◽  
Kirill Nikolaev ◽  
Tengiz Tabagua ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Plastic Material ◽  
Breast Cancer Patients ◽  
Anterior Axillary Line ◽  
National Medical ◽  
Results Of Treatment ◽  
Implant Placement ◽  
Quality Of Medical Care ◽  
Low Incidence

Purpose: To analyze the results of treatment and the quality of medical care for breast cancer patients with breast reconstruction using thoracodorsal flap (TDF). Material and methods: The study was conducted on the basis of the N.N. Petrov National Medical Research Center of Oncology at the Department of Breast Tumors for the period 2016-2017. When using the reconstruction of the breast with the help of TDF the feature was the complete intersection of the muscle in the anterior-axillary line before closing the defect of the breast tissue but with the preservation of the thoracodorsal vascular sheaf. Surgical treatment was provided to 67 patients with breast cancer including after neoadjuvant therapy. Results: One-time reconstruction was performed in 16 (23.8%) patients under the organ-preserving surgery, mastectomy in two (2.9%) patients and mastectomy with implant placement in 27 (40.2%) patients. Delayed reconstruction of the breast: TDF in combination with the implant - 20 (29.8%), the use of TDF without an implant - 2 (2.9%) patients. Complications were observed in 6 (8.9%) patients. Conclusion: Reconstruction of the breast with TDF is the method of choice and priority for patients who underwent radiation therapy with a lack of integumentary tissues to cover the implant. TDF is a «good» plastic material and could be used in patients with severe defect of breast shape after organ-preserving surgery and mastectomy. TDF is characterized by a low incidence of complications. The use of TDF does not worsen the rehabilitation of patients and does not shift the timing of adjuvant treatment.

scholarly journals Right paraduodenal hernia with extensive bowel gangrene treated with staged surgery: a Bogota bag followed by resection in a low-resource setting

2021 ◽  
Vol 14 (4) ◽  
pp. e239250
Author(s):  
Vijay Anand Ismavel ◽  
Moloti Kichu ◽  
David Paul Hechhula ◽  
Rebecca Yanadi
Keyword(s):  
Plastic Material ◽  
Successful Outcome ◽  
Paraduodenal Hernia ◽  
Transparent Plastic ◽  
Low Resource ◽  
Entire Small Bowel ◽  
Resource Setting ◽  
Low Resource Setting ◽  
Right Paraduodenal Hernia ◽  
Bowel Gangrene

We report a case of right paraduodenal hernia with strangulation of almost the entire small bowel at presentation. Since resection of all bowel of doubtful viability would have resulted in too little residual length to sustain life, a Bogota bag was fashioned using transparent plastic material from an urine drainage bag and the patient monitored intensively for 18 hours. At re-laparotomy, clear demarcation lines had formed with adequate length of viable bowel (100 cm) and resection with anastomosis was done with a good outcome on follow-up, 9 months after surgery. Our description of a rare cause of strangulated intestinal obstruction and a novel method of maximising length of viable bowel is reported for its successful outcome in a low-resource setting.

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