Mode III fracture analysis by Trefftz boundary element method

This paper presents a hybrid Trefftz (HT) boundary element method (BEM) by using two indirect techniques for mode III fracture problems. Two Trefftz complete functions of Laplace equation for normal elements and a special purpose Trefftz function for crack elements are proposed in deriving the Galerkin and the collocation techniques of HT BEM. Then two auxiliary functions are introduced to improve the accuracy of the displacement field near the crack tips, and stress intensity factor (SIF) is evaluated by local crack elements as well. Furthermore, numerical examples are given, including comparisons of the present results with the analytical solution and the other numerical methods, to demonstrate the efficiency for different boundary conditions and to illustrate the convergence influenced by several parameters. It shows that HT BEM by using the Galerkin and the collocation techniques is effective for mode III fracture problems

Influência de fatores genéticos e ambientais sobre as características produtivas no rebanho eqüino do Exército Brasileiro Genetic and environmental effects on production traits of an equine herd of the Brazilian army

Objetivou-se estimar parâmetros genéticos e fenotípicos para peso e altura (4.860 registros) em cavalos de quatro grupos genéticos - Brasileiro de Hipismo (BH), Puro-Sangue Inglês (PSI), Hanoveriano (HAN) e Sem Raça Definida (SRD) - por meio de informações de 1629 animais do Exército Brasileiro coletadas entre 1977 e 2002. Foram considerados fixos os efeitos de ano e mês de nascimento, idade da mãe, sexo do potro, ano e mês de mensuração e grupo genético. O mês de nascimento não afetou a altura ou o peso na população, exceto nos animais mais velhos. O sexo influenciou a altura, mas não afetou o peso dos animais de 21 meses e dos adultos e a raça influenciou a altura somente nos animais de 18 a 21 meses de idade e nos adultos. A influência dos efeitos fixos foi menor nos animais BH que nos SRD. As herdabilidades para o peso dos animais BH foram altas nas diversas idades, mas foram baixas para a altura. O comportamento do peso e da altura foi semelhante para as raças BH e SRD. De modo geral, nos dois grupos genéticos (BH e SRD), a herdabilidade do peso aumentou conforme as faixas etárias.<br>This study aimed to estimate genetic and phenotypic parameters for weight and height (4860 records) of equines from four genetic groups: Brazilian Showjumper (BH), Thoroughbred (PSI), Hanoverian (HAN) and No Defined Breed (SRD). Data collected from 1977 to 2002 on 1629 animals was provided by the Brazilian Army. Models used for analyses included the fixed effects of month and year of foaling and measuring, age of dam, foal sex and genetic group. Foaling month did not affect height or weight of the horses, except for older animals. The sex effect influenced height but not weight of 21-month-old animals and adults. The genetic group influenced height between 18 and 21 months of age, as well as height of adults. BH was less influenced by environmental effects than SRD. Heritabilities for weights of BS were high at various ages, but were low for height. Overall, heritability estimates for weight of BH and SRD increased as age increased