  We introduce in this paper a new four-parameter generalized version of the
linear failure rate (LFR) distribution which is called Beta-linear failure rate
(BLFR) distribution. The new distribution is quite flexible and can be used
effectively in modeling survival data and reliability problems. It can have a
constant, decreasing, increasing, upside-down bathtub (unimodal) and
bathtub-shaped failure rate function depending on its parameters. It includes
some well-known lifetime distributions as special submodels. We provide a
comprehensive account of the mathematical properties of the new distributions.
In particular, A closed-form expressions for the density, cumulative
distribution and hazard rate function of the BLFR is given. Also, the $r$th
order moment of this distribution is derived. We discuss maximum likelihood
estimation of the unknown parameters of the new model for complete sample and
obtain an expression for Fishers information matrix. In the end, to show the
flexibility of this distribution and illustrative purposes, an application
using a real data set is presented.
