Flexible roll forming of an automotive component with variable depth

Roll forming is a cost and energy efficient process for the manufacture of Ultra High Strength Steel (UHSS) structural and crash components in the automotive industry. The conventional roll forming process is limited to component having constant cross-section, while the recently deveoped Flexible Roll Forming (FRF) process allows the production of components in which the section varies over the length of the aprt; this permits optimization in terms of strength and weight. There has been an uptake in FRF in the heavy vehicle industry for the production of long and high strength structural parts, but passenger car bodies are more complex and generally parts require variations in width and also in depth. The widespread application of FRF in the automotive industy therefore requires the forming of components that have intricate variations in profile depth over the length of the part.
This work is a first comprehensive study of the FRF of high strength structural components with variable depth. For this, the FRF of an automotive bumper section is analyzed numerically using the commercial software package COPRA® FEA RF. A detailed analysis of the distribution and history of plastic strain in longitudinal, transcerse and thickness directions is performed and related to the shape defects observed in the proecss. The analysis shows that when forming variable depth components, zones of compressive longitudinal strain exist that lead to wrinkling defects. These can be reduced by applying additional flange contact during the operation. In general the current work suggests that the FRF of high strength components with variable depth is possible and can compete with other forming methods currently used in the automotive industry.

Evolution of elastic modulus in roll forming

Roll forming is a continuous process in which a flat strip is incrementally bent to a desired profile. This process is increasingly used in automotive industry to form High Strength Steel (HSS) and Advanced High Strength Steel (AHSS) for structural components. Because of the large variety of applications of roll forming in the industry, Finite Element Analysis (FEA) is increasingly employed for roll forming process design. Formability and springback are two major concerns in the roll forming AHSS materials. Previous studies have shown that the elastic modulus (Young’s modulus) of AHSS materials can change when the material undergoes plastic deformation and the main goal of this study is to investigate the effect of a change in elastic modulus during forming on springback in roll forming. FEA has been applied for the roll forming simulation of a V-section using material data determined by experimental loading-unloading tests performed on mild, XF400, and DP780 steel. The results show that the reduction of the elastic modulus with pre-strain significantly influences springback in the roll forming of high strength steel while its effect is less when a softer steel is formed.

Prediction of mode I delamination resistance of z-pinned laminates using the embedded finite element technique

A new finite modelling approach is presented to analyse the mode I delamination fracture toughness of z-pinned laminates using the computationally efficient embedded element technique. In the FE model,each z-pin is represented by a single one-dimensional truss element that is embedded within the laminate. Each truss is given the material, geometric and spatial properties associated with the global crackbridging traction response of a z-pin in the laminate; this simplification provides a computationally efficient and flexible model where pin elements are independent of the underlying structural mesh for thelaminate. The accuracy of the FE modelling approach is assessed using mode I interlaminar fracture toughness data for a carbon-epoxy laminate reinforced with z-pins made of copper, titanium or stainless steel. The model is able to predict with good accuracy the crack growth resistance curves and fracture toughness properties for the different types of z-pinned laminate.

The study of thermal stresses in a single long elastic fiber embedded in an infinite matrix

This work considered the micro-mechanical behavior of a long fiber embedded in an infinite matrix. Using the theory of elasticity, the idea of boundary layer and some simplifying assumptions, an approximate analytical solution was obtained for the normal and shear stresses along the fiber. The analytical solution to the problem was found for the case when the length of the embedded fiber is much greater than its radius, and the Young's modulus of the matrix was much less than that of the fiber. The analytical solution was then compared with a numerical solution based on Finite Element Analysis (FEA) using ANSYS. The numerical results showed the same qualitative behavior of the analytical solution, serving as a validation tool against lack of experimental results. In general this work provides a simple method to determine the thermal stresses along the fiber embedded in a matrix, which is the foundation for a better understanding of the interaction between the fiber and matrix in the case of the classical problem of thermal-stresses.

Meshfree Method for Prediction of Thermal Properties of Porous Ceramic Materials

In the presented thesis work, meshfree method with distance fields is applied to create a novel computational approach which enables inclusion of the realistic geometric models of the microstructure and liberates Finite Element Analysis(FEA) from thedependance on and limitations of meshing of fine microstructural feature such as splats and porosity.Manufacturing processes of ceramics produce materials with complex porosity microstructure.Geometry of pores, their size and location substantially affect macro scale physical properties of the material. Complex structure and geometry of the pores severely limit application of modern Finite Element Analysis methods because they require construction of spatial grids (meshes) that conform to the geometric shape of the structure. As a result, there are virtually no effective tools available for predicting overall mechanical and thermal properties of porous materials based on their microstructure. This thesis is a separate handling and controls of geometric and physical computational models that are seamlessly combined at solution run time. Using the proposedapproach we will determine the effective thermal conductivity tensor of real porous ceramic materials featuring both isotropic and anisotropic thermal properties. This work involved development and implementation of numerical algorithms, data structure, and software.

Factors influencig software migration decision: case studies of acerlormittal Tubarão and the city government of Serra, Espirito Santo

The objective of this research is to identify the factors that influence the migration of free software to proprietary software, or vice-versa. The theoretical framework was developed in light of the Diffusion of Innovations Theory (DIT) proposed by Rogers (1976, 1995), and the Unified Theory of Acceptance and Use of Technology (UTAUT) proposed by Venkatesh, Morris, Davis and Davis (2003). The research was structured in two phases: the first phase was exploratory, characterized by adjustments of the revised theory to fit Brazilian reality and the identification of companies that could be the subject of investigation; and the second phase was qualitative, in which case studies were conducted at ArcelorMittal Tubarão (AMT), a private company that migrated from proprietary software (Unix) to free software (Linux), and the city government of Serra, in Espírito Santo state, a public organization that migrated from free software (OpenOffice) to proprietary (MS Office). The results show that software migration decision takes into account factors that go beyond issues involving technical or cost aspects, such as cultural barriers, user rejection and resistance to change. These results underscore the importance of social aspects, which can play a decisive role in the decision regarding software migration and its successful implementation.

Applicability of an assessment model for healthcare information systems in a public hospital

Assessment processes are essential to guarantee quality and continuous improvement of software in healthcare, as they measure software attributes in their lifecycle, verify the degree of alignment between the software and its objectives and identify unpredicted events. This article analyses the use of an assessment model based on software metrics for three healthcare information systems from a public hospital that provides secondary and tertiary care in the region of Ribeirão Preto. Compliance with the metrics was investigated using questionnaires in guided interviews of the system analysts responsible for the applications. The outcomes indicate that most of the procedures specified in the model can be adopted to assess the systems that serves the organization, particularly in the attributes of compatibility, reliability, safety, portability and usability.

Improving IT process management through value stream mapping approach: A case study

Value-Stream mapping (VSM) is a helpful tool to identify waste and improvement areas. It has emerged as a preferred way to support and implement the lean approach. While lean principles are well-established and have broad applicability in manufacturing, their extension to information technology is still limited. Based on a case study approach, this paper presents the implementation of VSM in an IT firm as a lean IT improvement initiative. It involves mapping the current activities of the firm and identifying opportunities for improvement. After several interviews with employees who are currently involved in the process, current state map is prepared to describe the existing problem areas. Future state map is prepared to show the proposed improvement action plans. The achievements of VSM implementation are reduction in lead time, cycle time and resources. Our finding indicates that, with the new process change, total lead time can be reduced from 20 days to 3 days – 92% reduction in overall lead time for database provisioning process.

A novel latent factor model for recommender system

Matrix factorization (MF) has evolved as one of the better practice to handle sparse data in field of recommender systems. Funk singular value decomposition (SVD) is a variant of MF that exists as state-of-the-art method that enabled winning the Netflix prize competition. The method is widely used with modifications in present day research in field of recommender systems. With the potential of data points to grow at very high velocity, it is prudent to devise newer methods that can handle such data accurately as well as efficiently than Funk-SVD in the context of recommender system. In view of the growing data points, I propose a latent factor model that caters to both accuracy and efficiency by reducing the number of latent features of either users or items making it less complex than Funk-SVD, where latent features of both users and items are equal and often larger. A comprehensive empirical evaluation of accuracy on two publicly available, amazon and ml-100 k datasets reveals the comparable accuracy and lesser complexity of proposed methods than Funk-SVD.

Internet das Coisas aplicada a negócios – Um estudo bibliométrico

The Internet of Things is a technological innovation, based on artifacts and consolidated concepts like Internet and Smart Objects. Its growing business application of Internet of Things makes necessary to evaluate the strategy, benefits and challenges of this technology application. The main objective of this paper is to present the definition of Internet of Things, based on the most cited articles and as a secondary objective, present publication statistics classified by year and related terms, like ubiquitous computation. One of the conclusions is that papers related to business represent only 5% of all the papers analyzed by this research, considering just the papers published on journals. It shows that there is a great field to research on Business Administration.

Entrepreneurship in project management systems: proposal of a model and preliminary empirical evidence

This study analyzes the manifestation of the dimensions of Entrepreneurial Orientation (EO) and Project Management Systems (PMS). We used a qualitative approach to conduct exploratory research through a study in literature and a pilot case in a software company. Data was collected from semi structured interviews, documents, and records on file, then triangulated and treated with content analysis. The model proposed for the relationship between the types of PMS (ad hoc, Classic PM, innovation, entrepreneurship/intrapreneurship) and the dimensions of EO (innovativeness, risk-taking, proactiveness, competitive aggressiveness, and autonomy), was partially corroborated by empirical studies. New studies are suggested to validate the applicability and setup of the model.

Favorability conditions in the adoption of agile method practices for software development in a public banking

The main purpose of this paper is to propose and test a model to assess the degree of conditions favorability in the adoption of agile methods to develop software where traditional methods predominate. In order to achieve this aim, a survey was applied on software developers of a Brazilian public retail bank. Two different statistical techniques were used in order to assess the quantitative data from the closed questions in the survey. The first, exploratory factorial analysis validated the structure of perspectives related to the agile model of the proposed assessment. The second, frequency distribution analysis to categorize the answers. Qualitative data from the survey opened question were analyzed with the technique of qualitative thematic content analysis. As a result, the paper proposes a model to assess the degree of favorability conditions in the adoption of Agile practices within the context of the proposed study.

What Influences Information Security Behavior? A Study with Brazilian Users

The popularization of software to mitigate Information Security threats can produce an exaggerated notion about its full effectiveness in the elimination of any threat. This situation can result reckless users behavior, increasing vulnerability. Based on behavioral theories, a theoretical model and hypotheses were developed to understand the extent to which human perception of threat, stress, control and disgruntlement can induce responsible behavior. A self-administered questionnaire was created and validated. The data were collected in Brazil, and complementary results regarding similar studies conducted in USA were found. The results show that there is influence of information security orientations provided by organizations in the perception about severity of the threat. The relationship between threat, effort, control and disgruntlement, and the responsible behavior towards information security was verified through linear regression. The contributions also involve relatively new concepts in the field and a new research instrument.