Estimating Local Part Thickness in Midplane Meshes for Finite Element Analysis

Within the development of motor vehicles, crash safety (e.g. occupant protection, pedestrian protection, low speed damageability), is one of the most important attributes. In order to be able to fulfill the increased requirements in the framework of shorter cycle times and rising pressure to reduce costs, car manufacturers keep intensifying the use of virtual development tools such as those in the domain of Computer Aided Engineering (CAE). For crash simulations, the explicit finite element method (FEM) is applied. The accuracy of the simulation process is highly dependent on the accuracy of the simulation model, including the midplane mesh. One of the roughest approximations typically made is the actual part thickness which, in reality, can vary locally. However, almost always a constant thickness value is defined throughout the entire part due to complexity reasons. On the other hand, for precise fracture analysis within FEM, the correct thickness consideration is one key enabler. Thus, availability of per element thickness information, which does not exist explicitly in the FEM model, can significantly contribute to an improved crash simulation quality, especially regarding fracture prediction. Even though the thickness is not explicitly available from the FEM model, it can be inferred from the original CAD geometric model through geometric calculations. This paper proposes and compares two thickness estimation algorithms based on ray tracing and nearest neighbour 3D range searches. A systematic quantitative analysis of the accuracy of both algorithms is presented, as well as a thorough identification of particular geometric arrangements under which their accuracy can be compared. These results enable the identification of each technique’s weaknesses and hint towards a new, integrated, approach to the problem that linearly combines the estimates produced by each algorithm.

Improving FEM crash simulation accuracy through local thickness estimation based on CAD data

In this paper, we present a method for estimating local thickness distribution in nite element models, applied to injection molded and cast engineering parts. This method features considerable improved performance compared to two previously proposed approaches, and has been validated against thickness measured by di erent human operators. We also demonstrate that the use of this method for assigning a distribution of local thickness in FEM crash simulations results in a much more accurate prediction of the real part performance, thus increasing the bene ts of computer simulations in engineering design by enabling zero-prototyping and thus reducing product development costs. The simulation results have been compared to experimental tests, evidencing the advantage of the proposed method. Thus, the proposed approach to consider local thickness distribution in FEM crash simulations has high potential on the product development process of complex and highly demanding injection molded and casted parts and is currently being used by Ford Motor Company.

The impact of size and age of the company on assessing financial risk

Textiles and tourism sectors are two important sectors in Portuguese economy. Its high exposure to both internal and international economy volatility transform the companies operating in these economic sectors especially vulnerable to recent economic crises in Portugal and European Union. The objective of this paper is to evaluate and understand the impact of size and age on the financial health of textile and tourism companies, measured by economic indices. An empirical based model is proposed. Its implications are derived and tested on a sample of 4061 Portuguese companies from textile and tourism sector, during the period 2005-2009. The results conclude that age has a stronger impact on the risk of failure than size. Whereas the effect of age is generally positive regarding the financial health of the company, the effect of size is less clear and depends on the age of the company.

Economic analysis of occupational risk prevention: a case study in a textile company

Work accidents affect business and society as a whole. Fewer accidents mean fewer sick leaves, which results in lower costs and less disruption in the production process, with clear advantages for the employer. But workers and their households bear also a significant burden following a work accident, only partially compen-sated by insurance systems. Furthermore, the consequences of work accidents to the State and Society need also to be considered. When an organization performs an integrated risk analysis in evaluating its Occupational Health and Safety Management System, several steps are suggested to address the identified risk situations. Namely, to avoid risks, a series of preventive measures are identified. The organization should make a detailed analysis of the monetary impact (positive or negative) for the organization of each of the measures considered. Particularly, it is also important to consider the impact of each measure on society, involving an adequate eco-nomic cost-benefit analysis. In the present paper, a case study in a textile finishing company is presented. The study concentrates on the dyeing and printing sections. For each of the potential risks, several preventive measures have been identified and the corresponding costs and benefits have been estimated. Subsequently, the Benefit/Cost ratio (B/C) of these measures has been calculated, both in financial terms (from the organisa-tion’s perspective) and in economic terms (including the benefits for the worker and for the Society). Results show that, while the financial analysis in terms of the company does not justify the preventive measures, when the externalities are taken into account, the B/C ratio increases significantly and investments are fully justified.

The impact of size and age of the company on assessing financial risk.

Textiles and tourism sectors are two important sectors in Portuguese economy. Its high exposure to both internal and international economy volatility transform the companies operating in these economic sectors especially vulnerable to recent economic crises in Portugal and European Union. The objective of this paper is to evaluate and understand the impact of size and age on the financial health of textile and tourism companies, measured by economic indices. An empirical based model is proposed. Its implications are derived and tested on a sample of 4061 Portuguese companies from textile and tourism sector, during the period 2005-2009. The results conclude that age has a stronger impact on the risk of failure than size. Whereas the effect of age is generally positive regarding the financial health of the company, the effect of size is less clear and depends on the age of the company.